Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 89b98db95cbdb721…

MALICIOUS

RTF / .DOC

26.3 KB First seen: 2022-12-01
MD5: d6da005d2837f3072cc17fc7d9cfb7a8 SHA-1: 36e19ffaaa91d81fa8bfc79202b947456aac8d43 SHA-256: 89b98db95cbdb721abb8f686e0a7b7ab2aadebf73865b738d09ee27ee3c8768e
200 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 that exploits the Equation Editor vulnerability (CVE-2017-11882). The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware. The embedded object's ProgID, 'EQUAtioN.3', is a strong indicator of this specific exploit.

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.
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off00004c38.bin
9da05b8d9afa2327e491a5020a4aec32ffd81adb565f0871a8f565c956be87d9		 rtf-objdata-decoded RTF \objdata at offset 0x4C38 1646 bytes

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