Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 4bcd39b8d1e6d760…

MALICIOUS

RTF / .DOC

27.3 KB First seen: 2022-11-30
MD5: 2293c8841a2069aa6d72fd7cda76c11f SHA-1: 95326e768c840eede546dc9442b8751b30700ecd SHA-256: 4bcd39b8d1e6d760719af24e64353650f7defa9dd3342e6cf58b4b6d92315ed0
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The file is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The document also contains a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. The embedded object is likely designed to download and execute a secondary payload, although no specific script or URL was directly extracted.

Heuristics 6

  • 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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000054bb.bin
2d50acd9147169eaeb1f59fce56defde66194efbecb0817fedfaaca599397407		 rtf-objdata-decoded RTF \objdata at offset 0x54BB 1758 bytes

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