Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c9ea72740fd3081c…

MALICIOUS

RTF / .DOC

3.9 KB First seen: 2023-03-06
MD5: 200ce6695a851aedfc4e0cb6b41280f4 SHA-1: d0b35c07433ad2e297154231d63048b19fa4c5cb SHA-256: c9ea72740fd3081cdc882d459bb3b7c292c51aec18afe7fc6446eebe37d8200d
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains an embedded OLE object with an obfuscated Equation Editor ProgID, strongly indicating exploitation of CVE-2017-11882. The presence of \objupdate further suggests that the embedded object is designed to be activated, leading to arbitrary code execution. No specific malware family could be identified, but the exploit is a common initial access vector.

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_off0000007e.bin
2fc5b289eebbc0dca0405343003b9b769f57fdc5c34cc71392715cac491ebc0e		 rtf-objdata-decoded RTF \objdata at offset 0x7E 1874 bytes

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