Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8a3c9272734e9770…

MALICIOUS

RTF / .DOC

1.05 MB Created: 2019-09-17 13:59:00
MD5: bb53198d57f9a1cf5b645020c849c7fe SHA-1: acdda2c443da327bcf46092c4eb561405b06f676 SHA-256: 8a3c9272734e9770b1635e523f69fa1c0c94e730447e5c43f18c35db516875a0
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The file is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882 and CVE-2017-8759) to achieve code execution. The presence of OLE object data and specific RTF heuristics strongly indicate exploitation of these known vulnerabilities. The document body is heavily obfuscated and does not provide direct clues to the payload's intent, 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_off00103acc.bin
e77ca092948f175ff1c5aaaae3da57eb1bbea48b719bb434def31b4c0277946a		 rtf-objdata-decoded RTF \objdata at offset 0x103ACC 1485 bytes

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