Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5f0c86c01bc2fa6e…

MALICIOUS

RTF / .DOC

11.8 KB
MD5: fcd2b99d445efca2f30bf07a911356a8 SHA-1: 95af0ef117be6d06a9948f2e0eb2391a1a9d63bf SHA-256: 5f0c86c01bc2fa6ea9419e1a2afa5901015b4742c7b93a16650a7f9927d4ee8a
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an RTF document that contains embedded OLE object data, specifically targeting the Equation Editor. Heuristics indicate the exploitation of CVE-2017-11882, which allows for arbitrary code execution. The presence of `eQuaTIon.3` as a class name strongly suggests this exploit.

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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000011bf.bin
8c99de18d33d5a988407de27f86b059d3c250b8d86ab920b1c36cd0a27814358		 rtf-objdata-decoded RTF \objdata at offset 0x11BF 1510 bytes

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