Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 480b3bd2bfc9d04e…

MALICIOUS

RTF / .DOC

4.4 KB First seen: 2022-09-28
MD5: 632f8475a38c0f0f5a65753b1f2f59c2 SHA-1: 85b5973598ff7d4b191891f415618d8bcfb5744d SHA-256: 480b3bd2bfc9d04e00c239a5aa0fad23485efced48c65fe3e958415d7bca15de
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The RTF document contains an OLE object with an obfuscated Equation Editor ProgID, specifically triggering CVE-2017-11882. The ".objupdate" directive forces the activation of this embedded object, leading to arbitrary code execution. No specific malware family was identified, but the exploit is characteristic of exploit-laced documents.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000007c.bin
301258dd5957ae3860d26aa55a99d21617be07beffadc1e3a8456712c2662e6e		 rtf-objdata-decoded RTF \objdata at offset 0x7C 1947 bytes

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