Malicious RTF — malware analysis report

Static analysis result for SHA-256 1d3aeb44b55bd3eb…

MALICIOUS

RTF

226.1 KB Authoring application: Riched20 6.3.9600 First seen: 2021-06-17
MD5: 8e41237c9b035f649fb3bd77472479e1 SHA-1: 934e88795db2e1cda3b2db7ae06954ceb749178f SHA-256: 1d3aeb44b55bd3ebfaaf9b9082f57ac351e39903a8193419da3ad368c927d2cb
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file is an RTF document containing an embedded OLE object that leverages Microsoft Equation Editor. Critical heuristics indicate exploitation of CVE-2018-0802 via the Equation Editor object, which is designed to execute arbitrary code. This strongly suggests the document is a malicious attachment intended to exploit this vulnerability for initial execution.

Heuristics 6

  • ClamAV: Rtf.Exploit.CVE_2018_0802-6624871-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2018_0802-6624871-1
  • Equation Editor object class critical RTF_OBJCLASS_EQUATION
    Object class 'equation.3' references Equation Editor
  • Equation Editor ProgID + OLE object high RTF_EQUATION_EDITOR
    RTF references Equation.3 ProgID alongside \objdata — likely Equation Editor (CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798) but without the binary CLSID payload, so flagged at HIGH instead of CRITICAL.
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000100.bin rtf-objdata-decoded RTF \objdata at offset 0x100 16864 bytes
SHA-256: 3a9c6cec3695c70e0ebe5967fa33f6b8e08d0f56ababf34dc654b1e477f18367

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