Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b1f3e80dd112558e…

MALICIOUS

RTF / .DOC

74.4 KB First seen: 2023-10-16
MD5: e7509d2d6c37e2dd184956626b789ed7 SHA-1: 8ad644f138701723553df6ff0108b7fdc721df61 SHA-256: b1f3e80dd112558eda1297ffd4a0cbd2b04882bf651108f5d5108288a39abfa1
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File T1059.005 PowerShell

The sample is an RTF document that contains an embedded OLE object, specifically exploiting the Equation Editor vulnerability. The document body attempts to deceive the user into enabling editing and macros by discussing financial audits, a common lure. The presence of \objupdate indicates an attempt to automatically activate the embedded OLE object, likely to trigger the 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_off00002ae0.bin
b6e35e7dd2181517cd6c1f610386f126d5a6e986f0feb4d4e960e1ad620ff439
rtf-objdata-decoded RTF \objdata at offset 0x2AE0 1575 bytes