Malicious RTF — malware analysis report

Static analysis result for SHA-256 f4290fc951a648a6…

MALICIOUS

RTF

26.7 KB First seen: 2023-01-10
MD5: d7abdf1d9ce7bdd409a1faa8651bea5f SHA-1: d70b7e50e5d2532b042d0847368f189a5880cd1f SHA-256: f4290fc951a648a68e16ed49646f7c96656189cce852fc0c774f5fada5b23c12
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The RTF document contains an embedded OLE object specifically identified as related to CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. The presence of \objupdate and the specific class 'equAtIOn.3' strongly indicate an attempt to exploit this vulnerability. The document also contains a lure instructing the user to 'Enable editing', suggesting it's a dropper designed to bypass security measures and execute a malicious payload.

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_off000042b1.bin
284d17b73a5762a555f992432111262414dc5ca877a90c229c92f53d58d3be8e		 rtf-objdata-decoded RTF \objdata at offset 0x42B1 1421 bytes

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