Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 947eccd753ed8ea7…

MALICIOUS

RTF / .DOC

49.7 KB First seen: 2022-11-02
MD5: 29ac2cb199959db007b356c72c6c37f4 SHA-1: a19fb4017df984a78807cef241b34553ac1be55b SHA-256: 947eccd753ed8ea7cc0ec6fbfa13e3587b6eca248be36609c1bac44485691432
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains embedded OLE object data and specifically triggers heuristics related to Equation Editor exploitation, strongly indicating the use of CVE-2017-11882. The activation of this object via \objupdate suggests a mechanism for arbitrary code execution. While no specific malware family is identified, the exploit's nature points towards a downloader or initial access vector.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001400.bin
d870ec10b4677390f548b1cb06b3d4c2d398fb829a1c93c1c7cba519163a2b24		 rtf-objdata-decoded RTF \objdata at offset 0x1400 1658 bytes

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