Malicious RTF — malware analysis report

Static analysis result for SHA-256 5bf7aa1de7a064a9…

MALICIOUS

RTF

3.5 KB First seen: 2022-12-09
MD5: 69a6f3e5b30ab64fd90eb46dfec8d714 SHA-1: 9843c366b075bc145a5164be19052f8b441ef6e8 SHA-256: 5bf7aa1de7a064a956a29b7927a17b58c20b7cba96d74bd976ff920c41a34224
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains an embedded OLE object that triggers the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code upon activation, likely to download and run a secondary payload. The specific ProgID 'eQuAtion.3' was identified.

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_off00000075.bin
faf017afd242b814695a35b7f42981efafd66222593e074c3f0d96d20ac93746		 rtf-objdata-decoded RTF \objdata at offset 0x75 1679 bytes

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