Malicious RTF — malware analysis report

Static analysis result for SHA-256 c18a88fef1d4479c…

MALICIOUS

RTF

46.6 KB First seen: 2023-07-10
MD5: 4c346dedb60a0880ed8cab320f11c666 SHA-1: c81466adb3294abbd8dd5f9df95fc351b54d17cf SHA-256: c18a88fef1d4479c7a6a16f8600977b586999d0f72f8a9f844d156a6c4437d1e
180 Risk Score

Malware Insights

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

The RTF document contains heuristics indicating the presence of an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. The presence of `RTF_EQUATION_EDITOR` and `RTF_OBJUPDATE` strongly suggests an attempt to exploit a known vulnerability for initial execution.

Heuristics 5

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00005c7c.bin
1fac9cf1740463bc853bd24730b2690b4a57dd4dda780295bd940f710bb00611
rtf-objdata-decoded RTF \objdata at offset 0x5C7C 1897 bytes