Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c5ac325f7f37b3f9…

MALICIOUS

RTF / .DOC

26.9 KB First seen: 2022-12-29
MD5: bb468a442458f7bd8ce08fb198836a54 SHA-1: 54ef65b2f7c0857e07d9bb095d4e321424d40cd4 SHA-256: c5ac325f7f37b3f99cb0ac8a5b84b7cff2303b21e0bff754e6564f6c53c6fc35
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 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', which is a common tactic to bypass macro security. The embedded object is specifically identified as related to CVE-2017-11882 activation, indicating the document's primary purpose is to leverage this known exploit 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_off000050d9.bin
d6f0e3684f5b61713951809bbef50e019faef6e0d0e5e36b840991ffda8e5e29		 rtf-objdata-decoded RTF \objdata at offset 0x50D9 1741 bytes

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