Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3818e7bc26a06d57…

MALICIOUS

RTF / .DOC

57.7 KB First seen: 2023-09-07
MD5: 7f0164a8c458478898f4da56ed444626 SHA-1: cd5673fca2bae727d5f83b071320ca093cc41e90 SHA-256: 3818e7bc26a06d573b80d3c4a4cf39fd928bd7321757f696eb0d6b67eee3634c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1204.002 Malicious File T1059 Command and Scripting Interpreter T1059.005 Visual Basic

The sample is an RTF document that leverages OLE object data and an Equation Editor vulnerability to execute malicious content. The document body attempts to socially engineer the user into enabling editing and macros by discussing financial auditing, a common lure to bypass security measures. The presence of RTF_OBJDATA, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly indicates the exploitation of an OLE object for malicious purposes.

Heuristics 4

  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003ceb.bin
598f69cebaa7b281646d63a044e5f85a797bfb94afef63981fddc98cdc40cb4a
rtf-objdata-decoded RTF \objdata at offset 0x3CEB 1776 bytes