Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b13f7e12456114da…

MALICIOUS

RTF / .DOC

11.2 KB First seen: 2022-04-14
MD5: 350fb22970b8764a82c4a9ad4e7b8d5a SHA-1: e043b3485849626d4e00a456dbb08e3ed7caccd2 SHA-256: b13f7e12456114da7b500d2e50c74be39d0c148655f99d8eab1e09b02c1f1665
121 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that leverages the Equation Editor vulnerability, as indicated by the RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristic firings. The presence of OLE object data further supports this. The primary attack vector appears to be exploitation for client execution, likely leading to the download of a secondary payload, though no specific script or URL was directly extractable from the provided evidence.

Heuristics 3

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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001c2a.bin
2e91e6c4ac4bd43521d6fd717d8fa2e301e89149e9f8951f93e4608a508fc5b8
rtf-objdata-decoded RTF \objdata at offset 0x1C2A 1909 bytes