Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c4fe896ba8c3def6…

MALICIOUS

RTF / .DOC

27.3 KB First seen: 2022-11-10
MD5: 8a1993fff4b2e67ea289bfe7592545b7 SHA-1: b64e760a3265696feaa4a7fcbb1e1ef64693d069 SHA-256: c4fe896ba8c3def6dbc57105032ec621c6d61b142d2591dff98177f99fa8b121
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic

The file is an RTF document containing an embedded OLE object, specifically targeting the Microsoft Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic to bypass security measures and trigger the exploit. The presence of RTF_OBJDATA, RTF_OBJUPDATE, and RTF_EQUATION_EDITOR heuristics strongly indicates an attempt to leverage this known vulnerability for initial execution.

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_off000059b0.bin
b543153f0a01371f57b55fd014431b976cfad65185530f157a59c00b7cb3a87f
rtf-objdata-decoded RTF \objdata at offset 0x59B0 1402 bytes