Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8b1d9e9bab7ec0a0…

MALICIOUS

RTF / .DOC

3.9 KB
MD5: cac6aef4d756aa0484b6fa5cd4c8bba4 SHA-1: 6c79fcf3886babd27f36c32d719f06c35430ca71 SHA-256: 8b1d9e9bab7ec0a06444fecb7f6ee047226c5478413c28e7b308a33e2b87d6bc
180 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object. Heuristics indicate the exploitation of CVE-2017-11882 via the Equation Editor component. This vulnerability allows for arbitrary code execution when the document is opened, likely leading to the download and execution of a second-stage payload.

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 1 \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_off00000067.bin
24b4effb0562d1c8d3612298700a206f8463c91550cf90db17d4e6804b1ee58e		 rtf-objdata-decoded RTF \objdata at offset 0x67 1860 bytes

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