Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f4caaca12511a364…

MALICIOUS

RTF / .DOC

13.0 KB First seen: 2023-02-17
MD5: 9faddd060caaa8f6b2c285225e9d0fb3 SHA-1: cbe69cca8e39b881847a03a8f1214412d2c3976f SHA-256: f4caaca12511a364005bffaedeb802d4388e16f1bbf564386760619e9a15dccc
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The heuristic firings indicate the presence of an Equation Editor object and its activation via \objupdate, strongly suggesting exploitation for code execution. The specific ProgID 'EQUATioN.3' is a key indicator of this exploit.

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 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_off000012c2.bin
1af2dfe5aa47df3e56ebdeaaa77fc3f19df93d56dd379bcb29de68a8152fabe0		 rtf-objdata-decoded RTF \objdata at offset 0x12C2 1780 bytes

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