Malicious RTF — malware analysis report

Static analysis result for SHA-256 ff18b96950d524bf…

MALICIOUS

RTF

39.3 KB First seen: 2019-09-30
MD5: 5b1d33958995fa10f42ccd5dd5cc5092 SHA-1: 6652855e824f3e5a6407df12368d818299b02d25 SHA-256: ff18b96950d524bf9aa0f377588663afa4a36ec1cf23002c2a894d688012416f
360 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects, specifically triggering critical heuristics related to Equation Editor and CVE-2017-11882 and CVE-2017-8759. This indicates the file is designed to exploit these vulnerabilities for client-side code execution, likely delivered as a spearphishing attachment.

Heuristics 8

  • 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
  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • 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-7074033-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-7074033-0
  • Equation Editor object class critical RTF_OBJCLASS_EQUATION
    Object class 'hequation.x' references Equation Editor
  • \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_off0000026d.bin rtf-objdata-decoded RTF \objdata at offset 0x26D 3494 bytes
SHA-256: 949c1d59d8609fb916dfbcd7a623b6009b90803c6adf914ebb2958f48d36f5ea

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