Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0303225e6c988475…

MALICIOUS

RTF / .DOC

3.5 KB First seen: 2023-01-16
MD5: 2a65a183da1b93a22f961312c81aaec9 SHA-1: 48c2f92819d512304326f4e55ef4f32536f46367 SHA-256: 0303225e6c988475f329d5ad5b862a36419456af76508bcace25ff72401dcd7f
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model

The RTF document contains an embedded OLE object with an obfuscated Equation Editor ProgID, strongly indicating exploitation of CVE-2017-11882. The presence of ".objdata" and ".objupdate" directives further confirms the intent to activate the embedded object and execute arbitrary code. No specific family could be identified, but the exploit vector is clear.

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_off00000076.bin
3b319f68af64b4a73af625182bea7c0e185350b4d232b63f23a9934a9b594950		 rtf-objdata-decoded RTF \objdata at offset 0x76 1669 bytes

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