Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3b54636bd73ed3a0…

MALICIOUS

RTF / .DOC

8.8 KB First seen: 2023-01-06
MD5: 605e3fe1b1eac93d85b09e193b1aab03 SHA-1: 76158308cef94b1cb426d4033abed8a0ae883940 SHA-256: 3b54636bd73ed3a0c47f50479696ed9e9a2d1443488abceb6acda51d6efd4a36
200 Risk Score

Malware Insights

The RTF document contains an embedded OLE object that exploits CVE-2017-11882 through the Equation Editor. The document body contains a lure instructing the user to enable editing, which is a common technique for macro-based malware. The embedded object's ProgID, 'EquatIoN.3', is a strong indicator of this specific exploit.

Heuristics 6

  • 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.
  • \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_off000013f9.bin
ed3bb95d0bb97055e6ad2f505d131cf86895f92c565a96d16f920e99213d4814		 rtf-objdata-decoded RTF \objdata at offset 0x13F9 1911 bytes

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