Malicious RTF — malware analysis report

Static analysis result for SHA-256 de9a977c672758a7…

MALICIOUS

RTF

22.8 KB First seen: 2022-11-29
MD5: 651c9a6ce618676610f649779edc714b SHA-1: cd74ad99acc4c1caf5e8379367b9df24f07746db SHA-256: de9a977c672758a706c96568e202c075590bb60a848fb3b7680c2f83df7f203e
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model

The RTF document contains embedded OLE object data, specifically targeting the Equation Editor component. High-confidence heuristics indicate the activation of CVE-2017-11882, a known vulnerability that allows for arbitrary code execution when the Equation Editor is activated. The document also contains a lure instructing the user to 'Enable editing', a common tactic to bypass security measures and trigger the exploit.

Heuristics 6

  • 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
  • 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_off00004731.bin
041653922e472e0761fbc8a5f3b653981301b62764f72b268fc3ace5665ce8c4		 rtf-objdata-decoded RTF \objdata at offset 0x4731 1434 bytes

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