Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f31d3036ff56f57b…

MALICIOUS

RTF / .DOC

863.8 KB First seen: 2022-10-17
MD5: a2dc064c2eac83427391770fd867b6ed SHA-1: d2674dbf54ee6aef08dcba2e7e420d4d4d733055 SHA-256: f31d3036ff56f57b6a0e89a7ef742b619b1712e5b895179ba9ba2a335922b6cc
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains an embedded OLE object specifically targeting the Equation Editor vulnerability (CVE-2017-11882). This exploit is designed to execute arbitrary code, likely to download and run a secondary payload. The presence of OLE object data and explicit triggers for Equation Editor activation strongly indicate this exploit vector.

Heuristics 5

  • 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.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012b8.bin
417159f4ece8d912b6d551fad02f320a6c5b855d9c7b69cd6faef9f69a7bc2a1		 rtf-objdata-decoded RTF \objdata at offset 0x12B8 81223 bytes
objdata_01_off0002eede.bin
d541f40d3697d40fb5a5ae03df885a1ecc9c95b0c0f7dd7bfe86e66ff4cfbf9a		 rtf-objdata-decoded RTF \objdata at offset 0x2EEDE 141506 bytes

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