Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8e3fa133f76db430…

MALICIOUS

RTF / .DOC

20.4 KB First seen: 2022-10-12
MD5: 7d14762882b1b692e4f72492dbae2d65 SHA-1: 8e57fdacd2b25149775c261d32db58c1381da7e8 SHA-256: 8e3fa133f76db430c639e128a0897c91273e016f631420cb5f5371506c8d4887
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1566.001 Phishing: Spearphishing Attachment T1059.005 Command and Scripting Interpreter: Visual Basic

The file is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The document body contains a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. The exploitation of CVE-2017-11882 is a critical finding, strongly indicating the document's intent to execute malicious code.

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_off00001102.bin
5377be40530c82f123fadeb757cbd5659cca816fade5e562291dcb417fc2f040		 rtf-objdata-decoded RTF \objdata at offset 0x1102 1698 bytes

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