Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 36330fa71c2af722…

MALICIOUS

RTF / .DOC

3.9 KB First seen: 2022-04-14
MD5: a3fd7f716169052a23035d8a2ca33f0b SHA-1: 7bf80d3bc27b9c766a889eccbab24cfb09c8cbcf SHA-256: 36330fa71c2af722f4f5803d98b4743b52f6fbd9d616170d4491a8a3907fc7e2
160 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects and specifically triggers the Equation Editor vulnerability. The ".objupdate" directive forces the activation of the OLE object, which is likely to contain a malicious payload. The presence of the "RTF_EQUATION_EDITOR" heuristic strongly indicates exploitation of the Equation Editor component.

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.
  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000a7.bin
9974c3c274fb83db3d13aa50caf1f0c2c63db34079780093d328780e40ae10ab
rtf-objdata-decoded RTF \objdata at offset 0xA7 1682 bytes