Malicious RTF — malware analysis report

Static analysis result for SHA-256 c16bfc5c97dd0ee4…

MALICIOUS

RTF

27.2 KB First seen: 2020-09-07
MD5: 2b5b4e4e0814a07fb57590a27f134f38 SHA-1: b01439cf2906e51f69d298a2cbb7002402ae1b85 SHA-256: c16bfc5c97dd0ee447b858daeaae14962530922e87502802fa5148ebe5990518
260 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object that exploits CVE-2017-11882 through the Equation Editor. This is a known technique for executing arbitrary code. ClamAV identifies the file as Rtf.Dropper.Agent-8041672-0, indicating it functions as a dropper for further malicious activity. The specific payload or download URL is not directly extractable from this static analysis.

Heuristics 6

  • Split hex Equation Editor ProgID + OLE object critical CVE likely RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • 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.Dropper.Agent-8041672-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-8041672-0
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001e7c.bin rtf-objdata-decoded RTF \objdata at offset 0x1E7C 2056 bytes
SHA-256: b88551f352570886390ed4cb1ee174eedb233e4fe133edfcc4082b4b49eab1a2

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