Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 65c59f0cea800540…

MALICIOUS

RTF / .DOC

7.5 KB First seen: 2022-08-30
MD5: ca18f1b2c3a2cc153bdf4fafeff53cfa SHA-1: 7e69c377752ab91b156e47b331a86ffe68831cee SHA-256: 65c59f0cea8005400ed6d3625c4c8411948cc2dc472889da5c84061988fe16d7
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1566.002 Phishing: Spearphishing Link

The sample is an RTF document that exploits CVE-2017-11882 via the Equation Editor. The document contains an OLE object with `

Heuristics 6

  • 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.
  • 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.
  • 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 2 \objdata section(s) — embedded OLE objects
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000926.bin
eb593b26bd1abac3d9976aefe0f366ea77d220692c894b7d6a17f1a799cb2655		 rtf-objdata-decoded RTF \objdata at offset 0x926 1900 bytes

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