Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 85a9c86962ea71b5…

MALICIOUS

RTF / .DOC

31.6 KB First seen: 2023-04-28
MD5: fd5e7dec877d40fb79fb78ab877680c7 SHA-1: 51a42299563697d0b90727f61e82bef04f76316e SHA-256: 85a9c86962ea71b53cd5dfd7bb8aa43a4556b131ba2bf96ac54a430591e2c833
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1559.001 Component Object Model Hijacking

The sample is an RTF document that leverages OLE object embedding and specifically targets the Equation Editor vulnerability. The 'SE_ENABLE_LURE' heuristic indicates a social engineering tactic to trick the user into enabling content, which is necessary to trigger the exploit. The embedded OLE object and the specific Equation Editor heuristic strongly suggest an attempt to execute arbitrary code.

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_off00004e76.bin
2a279d0ece2278db50bb403db76e0a62513899a8f6cdc82bb1fdc6167f1ac2ea
rtf-objdata-decoded RTF \objdata at offset 0x4E76 1527 bytes