Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 9a38d5e0cd29c0fe…

MALICIOUS

RTF / .DOC

4.2 KB First seen: 2022-06-21
MD5: 8999f5e8dd6966a485198789952b782d SHA-1: 7c1eda192d9bf552ed1b35b11e21541637372a0f SHA-256: 9a38d5e0cd29c0fecb5a342d5aacf3c3a1b198db51cdd19dc699180a784498b6
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File Execution: Malicious File T1559.001 Component Object Model Hijacking: Component Object Model T1059.001 Command and Scripting Interpreter: PowerShell

The RTF document contains embedded OLE object data, specifically triggering the CVE-2017-11882 vulnerability through the Equation Editor. This exploit allows for the execution of arbitrary code, likely to download and run a second-stage payload. The presence of `eqUaTION.3` as a class name further confirms the exploitation of this known vulnerability.

Heuristics 5

  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000098.bin
dcd9c7f92035157426678d961b39860f984699a1e3acf582345fc5014d48a463		 rtf-objdata-decoded RTF \objdata at offset 0x98 1782 bytes

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