Malicious RTF — malware analysis report

Static analysis result for SHA-256 65ffbd2cec3a95b3…

MALICIOUS

RTF

14.5 KB First seen: 2019-10-01
MD5: 6863f7d934a39f34534d11fee17dadfd SHA-1: d18202c5edbb1bd2fe200e5f20fe07936a190503 SHA-256: 65ffbd2cec3a95b3cb91a94048c23aa0abaa7ed234b9607e3fb906b64ed78222
360 Risk Score

Malware Insights

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

The RTF file contains an embedded Equation Editor object, a known vector for exploiting CVE-2017-11882. The presence of RTF_EQUATION_EDITOR, RTF_OBJCLASS_EQUATION, and CVE_2017_11882_ACTIVATION_RELATED heuristics strongly indicates exploitation of this vulnerability. The embedded object is likely designed to execute a second-stage payload upon activation, leading to arbitrary code execution.

Heuristics 9

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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.
  • 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
  • Reference to WinExec API high SC_STR_WINEXEC
    Reference to WinExec API
  • \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
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000088.bin rtf-objdata-decoded RTF \objdata at offset 0x88 6399 bytes
SHA-256: bbcebe898927637dddd87352f80c157121f41e75fb7f14c5d8e98b79396b46f8

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