Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 db064c620f949359…

MALICIOUS

RTF / .DOC

52.8 KB First seen: 2023-01-23
MD5: 59ea2980dcb26a8a5f2f0af034e727db SHA-1: e986e47eaba8d23d7d999745d27b1079d628cd54 SHA-256: db064c620f9493591ffef1dca3386c0fbc405e6d71f9b76d06c5f03737115938
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1059 Command and Scripting Interpreter

The file is an RTF document that leverages the CVE-2017-11882 vulnerability in the Microsoft Equation Editor. The document contains a lure instructing the user to 'Enable editing' to view its content, which is a common technique to bypass macro security settings. The presence of OLE object data and specific Equation Editor ProgIDs strongly indicates exploitation of this known vulnerability.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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
  • 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_off0000bc3b.bin
f8d6fbd743f1119902a5084e91e82b89294612d25fa0637807f1643b5c55f454		 rtf-objdata-decoded RTF \objdata at offset 0xBC3B 1679 bytes

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