Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 da2d98f266927aef…

MALICIOUS

RTF / .DOC

18.6 KB
MD5: b58c016cbcf77229d09a5270e007e5ce SHA-1: 99738c6a5f3c8d9ab0f402f0171064f78e6dbf5e SHA-256: da2d98f266927aef6e374edc0dfa54bd305ce7451dc620aefd289a991e6f6eb4
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains embedded OLE object data, specifically triggering heuristics related to Equation Editor. The critical heuristic 'RTF_EQUATION_EDITOR' and high heuristic 'CVE_2017_11882_ACTIVATION_RELATED' strongly indicate the exploitation of CVE-2017-11882 via the Equation Editor component. The ".objupdate" directive further suggests that the embedded object is designed to be activated automatically upon opening the document, leading to arbitrary code execution.

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.
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001ff4.bin
be1f5f546bff5a3a87b3909afb2394f12cc9fcca90cad29b1dfc0b7af6c29f25		 rtf-objdata-decoded RTF \objdata at offset 0x1FF4 1622 bytes

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