Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 65166539d41c59c2…

MALICIOUS

RTF / .DOC

1.69 MB Created: 2019-09-17 13:59:00
MD5: b640bb92b1d9abc7f985666283b1fea4 SHA-1: f2d1030b89f47acb96c05dc433bd6f2031cc7162 SHA-256: 65166539d41c59c23f1725ddc0012fbe63726d38755a1f2ea9a7abe42f0d85dc
242 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 heuristics related to Equation Editor and MSXML SAX OLE activation. This strongly indicates exploitation of CVE-2017-11882 and CVE-2017-8759, which are known to execute arbitrary code. The presence of `Equation.3` as a class name further supports this. No specific family could be identified, but the exploitation method is clear.

Heuristics 7

  • 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.
  • 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.
  • \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
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off001ad297.bin
cfb0fd10f6d175eb127d959779712881be33fe8ceb710148ab55838317a00b7c		 rtf-objdata-decoded RTF \objdata at offset 0x1AD297 1485 bytes

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