Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 faf71181b4aee21a…

MALICIOUS

RTF / .DOC

32.4 KB First seen: 2022-12-28
MD5: 1c8dff1ba5adb253c975739d5d9efe57 SHA-1: 77d3eb1a7c578f265ed939a163907172b0f2ff2f SHA-256: faf71181b4aee21a871a05e74566356faca82201252d20cb3ef1cd75dcef2b16
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document containing an embedded OLE object specifically identified as Equation Editor, triggering heuristics related to CVE-2017-11882. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware. The embedded OLE object is designed to be automatically activated, likely leading to the execution of a secondary payload.

Heuristics 6

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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 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_off00005041.bin
ef5adeb07a232c77289f8f88a4ea0007cc627baf41456bdaf6a2cd775c65a39c		 rtf-objdata-decoded RTF \objdata at offset 0x5041 1366 bytes

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