Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1c16e39a01bf2d8a…

MALICIOUS

RTF / .DOC

240.7 KB First seen: 2022-03-22
MD5: 01fb1c4b29b8c37345c7ece380fa1a90 SHA-1: 22e8449f659082d64b2bd23d667be0a21b91b0bd SHA-256: 1c16e39a01bf2d8a1a2ba030d54905a16db77970f9f5956af68ba1af34772c6d
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains embedded OLE objects, specifically triggering heuristics related to the Equation Editor vulnerability. The presence of \objupdate indicates that the embedded object is designed to be activated automatically, likely leading to the execution of arbitrary code. This is a common delivery mechanism for exploiting the Equation Editor vulnerability.

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_off00000090.bin
ab3a455f48bc99c6cfd96d4a3d6381d9820c99bbf7ca289ede114c6b8a28ed1b
rtf-objdata-decoded RTF \objdata at offset 0x90 71549 bytes