Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0f1779c06ae134cf…

MALICIOUS

RTF / .DOC

2.78 MB Created: 2019-09-17 13:59:00
MD5: 45733015ad3539d9c4942a11a52799ff SHA-1: a0f5d1bf81513fc72c1e10c0e64e74b4c7636076 SHA-256: 0f1779c06ae134cfa8b8eaf53ce8ca531389abf052716f43570a299bb7b93c30
242 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits CVE-2017-11882 and CVE-2017-8759. The presence of RTF_OBJDATA, RTF_EQUATION_EDITOR, and CVE_2017_11882_ACTIVATION_RELATED heuristics strongly indicates the exploitation of the Equation Editor vulnerability. The CVE_2017_8759 heuristic further points to exploitation via MSXML SAX OLE activation. These vulnerabilities allow for arbitrary code execution, likely to download and run a secondary payload.

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_off002adec4.bin
46a7cf4c26af2f7801da824510bcb6a7bfb854c8ef05fc87b54e00c425a8b869		 rtf-objdata-decoded RTF \objdata at offset 0x2ADEC4 1478 bytes

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