ObliqueRAT
ObliqueRAT
Hash: dfad2a80dac91e7703266197ebbf5d67ef77467ab341dd491ad25d92d8118cac
Maldoc
- Document file(docx) dropped the exe auto open -> deobfuscate -> write to file
- Ole file contains Stomped code for detail
- Contains suspicious strings for details
Deobfuscate Maldoc:
- use oledump to dump the data
python oledump.py -d -s 11 ~/Downloads/dfad2a80dac91e7703266197ebbf5d67ef77467ab341dd491ad25d92d8118cac.docx > stream11.bin
- Macros/UserForm1/o contians the obfuscated data for exe
- deobfuscate split with ‘O’ -> convet the int values to char -> write to file
olevba3 summary
+----------+--------------------+---------------------------------------------+
|Type |Keyword |Description |
+----------+--------------------+---------------------------------------------+
|AutoExec |Document_Close |Runs when the Word document is closed |
|AutoExec |Document_Open |Runs when the Word or Publisher document is |
| | |opened |
|AutoExec |UserForm_Click |Runs when the file is opened and ActiveX |
| | |objects trigger events |
|Suspicious|Environ |May read system environment variables |
|Suspicious|Open |May open a file |
|Suspicious|Write |May write to a file (if combined with Open) |
|Suspicious|Put |May write to a file (if combined with Open) |
|Suspicious|Binary |May read or write a binary file (if combined |
| | |with Open) |
|Suspicious|Shell |May run an executable file or a system |
| | |command |
|Suspicious|WScript.Shell |May run an executable file or a system |
| | |command |
|Suspicious|Call |May call a DLL using Excel 4 Macros (XLM/XLF)|
|Suspicious|MkDir |May create a directory |
|Suspicious|CreateObject |May create an OLE object |
|Suspicious|Windows |May enumerate application windows (if |
| | |combined with Shell.Application object) |
|Suspicious|Hex Strings |Hex-encoded strings were detected, may be |
| | |used to obfuscate strings (option --decode to|
| | |see all) |
|IOC |sgrmbrokr.exe |Executable file name |
|Suspicious|VBA Stomping |VBA Stomping was detected: the VBA source |
| | |code and P-code are different, this may have |
| | |been used to hide malicious code |
+----------+--------------------+---------------------------------------------+
Script to deobfuscate ole data
python3 deobfu.py stream11.bin
Written on May 18, 2021