Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 776c5e0b503498c9…

MALICIOUS

RTF / .DOC

26.4 KB First seen: 2022-12-05
MD5: 996b113dfcf00012539bbca65d886074 SHA-1: b05ce7726b68786c9ffbae7ae42ac4d18c6e1c39 SHA-256: 776c5e0b503498c97326589010eb397bbb756af1a8c49851ed7d4be56a8dc0b8
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The document body includes a lure instructing the user to 'Enable editing', a common tactic for macro-based malware. The embedded OLE object is specifically identified as related to Equation Editor activation, indicating a high likelihood of exploitation for initial execution.

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_off000048c5.bin
9e33c86f85a5f8881be28cc39521e7ac84f90a9d4153b212c862ba9ebf0bb72b		 rtf-objdata-decoded RTF \objdata at offset 0x48C5 1854 bytes

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