Malicious RTF — malware analysis report

Static analysis result for SHA-256 b813ccabea4c3109…

MALICIOUS

RTF

177.6 KB Authoring application: Riched20 6.3.9600 First seen: 2021-06-17
MD5: 4b9857e641d3061beccd2d7b8254894c SHA-1: 40790f6f8ea3ef590ba3d9aca6304e62898a73db SHA-256: b813ccabea4c310954586d906ba2c9106d24ed076e19bb3f4f68b971f14e3f25
240 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object specifically identified as Microsoft Equation Editor, triggering critical heuristics related to CVE-2018-0802. This indicates the file is designed to exploit this vulnerability for client-side code execution. The presence of the Equation Editor object and the associated ClamAV detection strongly suggest a malicious intent, likely delivered as a spearphishing attachment.

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 7979 bytes
SHA-256: ca0c56fb9ea374a99836066b856ba22953394d160c8943d39e66e6e4af2a2d5f

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