Skip to main content

Malicious document analysis Part - 1

Introduction 
A basic and quick approach to analyse phishing documents to identify indicators of maliciousness. FYI this post doesn't cover complete & in depth analysis of malicious documents

Tools 
  1. Didier Stevens Suite  
  2. sudo pip install oletools 
  3. Yara - A pattern matching Swiss knife 
Analysis 
All document samples are pulled from Hybrid Analysis - a free malware analysis service for the community that detects and analyzes unknown threats using a unique Hybrid Analysis technology. 

Hash 1: e07c84f98332b07ae40a22f15c32cbf794586e26576a7539def667881e15beae

Download above mentioned sample and check the integrity
Check the file properties using native Linux file command which gives quick idea about sample
Download Didier Stevens Suite and check for yara rules.
Run various rules against the sample document to identify any sort of maliciousness
The below rule can identify an executable file embedded in OLE objects
 Run above yara rule against the downloaded document
Observe the below maldoc.yara output
It's interesting to see few suspicious Imports in embedded in binary
Again run other rules to get more confidence about maliciousness of the document
Now it's time for oletools and run oledump.py 
A macro is observed in stream 8 and now run olevba  to see the macro
Observe an executable name 1.exe
Run oleobj to see file embedded in OLE object
It's always interesting to see the metadata about any suspicious document and especially when the document is modified
Run oletimes to see the modification  time of streams
Now it's time to dump the embedded exe file from document
 Dump using -d option with stream number 14  in oledump.py 
Open the dumped file in ghex an hexeditor and adjust the hex and ascii bytes to exe signature 4d5a at offset 0
Save as the file and run native file command and pecheck.py from Didier Stevens suite
pecheck.py can also parse the PE to preview it's imports
The extracted binary had been run on various sandboxes to identify any sort of maliciousness. Observe the below output from any.run

Report from Hybrid Analysis  and researchers confirm that  this malware variant belongs to hancitor downloader campaign. Below are indicators of compromise

  • wonyheghi,com
  • tontwoverar,ru
  • nofatiga,ru

Further analysis needs to be done to understand full functionality and characteristics of the specimen

Comments

  1. Diniz24 May 2019 at 04:54

    Great post. In step 10, oleobj extracted the Objects from the malicious file, although it's good to know that we can extract with oledump and adjust the file header.

    ReplyDelete

Post a Comment

Popular posts from this blog

Memory Analysis of WannaCry Ransomware

Introduction  This post explains the memory dump analysis of WannaCry infected system using volatility (An open source memory forensics framework) and other open source tools. It doesn't cover the analysis of initial infection vector, propagation and recovery of infected system. The objective is to leverage memory forensic analysis to uncover and extract Indicators of Compromise (IoC)  WannaCry  WannaCry (or WannaCrypt, WanaCrypt0r 2.0, Wanna Decryptor) is a ransomware program targeting the Microsoft Windows operating system. On Friday, 12 May 2017, a large cyber-attack using it was launched, infecting more than 230,000 computers in 150 countries, demanding ransom payments in the cryptocurrency bitcoin in 28 languages.The attack has been described by Europol as unprecedented in scale. https://en.wikipedia.org/wiki/WannaCry_ransomware_attack Discalimer You are dealing with real malware samples Don’t expose them to internal networks or internet Analyze them in a controlle
60 comments
Read more

Malicious office doc with process hollowing shellcode

Introduction  This post covers how to identify and extract shellcode manually from hancitor phishing office document. Refer  Part-1  and  Part-2  to get an understanding of  tools and approach to analyse phishing documents.  Tools  Didier Stevens Suite    sudo pip install oletools  Analysis   SHA256:  5d077b1341a6472f02aac89488976d4395a91ae4f23657b0344da74f4a560c8d   This sample contains encoded shellcode that starts a new (suspended) explorer.exe process, injects its own code (an embedded, encoded exe) and executes it.  This maldoc leverages  VBA macros  to execute its payload  and t he encoded shellcode is a property in stream 17.  T he shellcode uses WIN32 API functions like CreateProcess, ZwUnmapViewOfSection, GetThreadContext, ResumeThread etc. to inject code into the newly created process (explorer.exe) and execute it. This method is called process hollowing or process replacement.The explorer.exe process is created in a suspended state, the code for explore
1 comment
Read more

Memory dump analysis of Donny's System

Introduction  This post solves the mystery of Donny's System   and outlines how to utilize memory forensics methodology to uncover artifacts from memory dumps Tools: Volatility, Yara  & Windows Powershell Analysis Six-step investigative methodology by SANS Identify rogue processes  Analyze process DLLs and handles   Review network artifacts  Look for evidence of code injection  Check for signs of rootkit Dump suspicious processes and drivers  Run volatility  imageinfo plugin   to identify profile  PS C:\volatility> .\vol.exe -f .\unknown.vmem imageinfo Run Volatility  pslist plugin to see active running processes PS C:\volatility> .\vol.exe -f .\unknown.vmem --profile=WinXPSP3x86 pslist Just to remind that all process creation and termination timings are specified in UTC. Ensure to change them to system timezone while correlating the events with other sources of evidence game.exe clearly looks suspicious as it ran and exit in a short span o
Post a Comment
Read more