Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6aef022d6284a921…

MALICIOUS

RTF / .DOC

11.6 KB
MD5: 4a26cd352e0280addefccb37e01050ec SHA-1: 37002cdad754b0f9e68503de6c7cfd32f4e7a99f SHA-256: 6aef022d6284a921321f16f532d27db887743ef81aaf264eff8112ecaa785d4c
200 Risk Score

Malware Insights

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

The RTF document contains embedded OLE object data, specifically related to Microsoft Equation Editor. Heuristics indicate the exploitation of CVE-2017-11882, a known vulnerability in Equation Editor, which allows for arbitrary code execution. This is a common method for delivering secondary payloads, hence the high confidence in this attack pattern.

Heuristics 5

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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001c3d.bin
17b593179fd5b31923d2af29e1920a4dabe235e19fca215977529d41fe905dc2		 rtf-objdata-decoded RTF \objdata at offset 0x1C3D 1711 bytes

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