Malicious RTF — malware analysis report

Static analysis result for SHA-256 c2b77e9df88bfa3d…

MALICIOUS

RTF

3.0 KB First seen: 2023-01-16
MD5: 0d353aed51504b23436309bdd41e23f6 SHA-1: d3faf9797b7314f05e7102e26f5b7c0a135d0761 SHA-256: c2b77e9df88bfa3d27472676bd78894e695b5758b7c5f496082aed0c553b720d
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains OLE object data and specifically triggers the Equation Editor, indicating exploitation of CVE-2017-11882. This vulnerability allows for arbitrary code execution when the embedded object is activated. The presence of `equAtIon.3` as the ProgID strongly suggests this exploit.

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_off00000079.bin
e7b6f1e99ccedf026063dae8b9ae742f5aa5cb6dfe4d5d6fa25a57d9c359480e		 rtf-objdata-decoded RTF \objdata at offset 0x79 1434 bytes

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