Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f750ed5a3a351078…

MALICIOUS

RTF / .DOC

28.0 KB First seen: 2022-11-17
MD5: b49e046f4b6b95706f5105f407f7dfbe SHA-1: 9cfdc3047ee6c88347367d930b810395ad3b8139 SHA-256: f750ed5a3a35107886675b34757848dd7092b4cbc77453b39e342eac5a71d251
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 heuristic firings indicate that the document is designed to trigger this exploit upon opening, likely to achieve arbitrary code execution. The document body contains a lure to 'Enable editing', a common tactic to bypass macro security settings.

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_off0000526c.bin
f736953d4d934d83a762ee16739d4e0c55f38ef5292c63858766223967a0268a		 rtf-objdata-decoded RTF \objdata at offset 0x526C 1670 bytes

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