Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6fe9e36c1c630be7…

MALICIOUS

RTF / .DOC

29.9 KB First seen: 2022-12-15
MD5: 218e20eda473139ebc23ba5efbc9255f SHA-1: bcce17a380a0cb49898798fd79263cecbe9403b4 SHA-256: 6fe9e36c1c630be73b939d4a38ea8ba35e8407675bab4208254e882c317fc831
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object with a specific Equation Editor ProgID, triggering heuristics for RTF_EQUATION_EDITOR and RTF_OBJUPDATE. The SE_ENABLE_LURE heuristic indicates the document likely prompts the user to enable content, a common tactic for macro-based malware. The RTF_OBJDATA heuristic confirms the presence of embedded OLE object data, which is leveraged by the Equation Editor exploit.

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.
  • \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_off00005c38.bin
c6b7c35c43e4f43893166020eba89f428961be0a9d730a19e5d051827c270f03
rtf-objdata-decoded RTF \objdata at offset 0x5C38 1990 bytes