Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7349af6dc60588fa…

MALICIOUS

RTF / .DOC

11.5 KB First seen: 2022-12-10
MD5: d670e2d6cb29811a91e7c0e656e29331 SHA-1: 724794cccc05a58c8efe9bca12fb7a9967656dc3 SHA-256: 7349af6dc60588fa3864a72060bd2cb1899e8957c9dc04fd855f7c9a409429d1
200 Risk Score

Malware Insights

The sample is an RTF document containing an OLE object that exploits CVE-2017-11882 through the Equation Editor. The `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` heuristics confirm this vulnerability is targeted. The `RTF_OBJAUTLINK` and `RTF_OBJUPDATE` heuristics indicate that the OLE object is designed to be activated automatically, likely to execute a malicious payload. No document body text or scripts were extracted, but the exploit itself is sufficient evidence of malicious intent.

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_off00001ff5.bin
f465663b02fdc4d5c3f3a5fa1b0ae34f4b8bd750920c2ec56f0e83ca4bf01798		 rtf-objdata-decoded RTF \objdata at offset 0x1FF5 1763 bytes

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