Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 2255f2bc6cddd35c…

MALICIOUS

RTF / .DOC

13.9 KB First seen: 2022-08-31
MD5: f47f8a107644dd4f44f39d588351f570 SHA-1: 83441e13f16fc5a75f8f2c03cf7c4b86e5378217 SHA-256: 2255f2bc6cddd35c18a33fcd907e4a26aa8e6f776bbf8b7b3f53a06d9c52641b
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits CVE-2017-11882 through the Equation Editor. The document body contains a lure instructing the user to enable editing, a common tactic for macro-based malware. The exploit's activation is directly indicated by multiple heuristic firings, suggesting a high likelihood of payload execution.

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_off00002075.bin
7655a3ba7892167d1fb39691677140fdd88455c3f81ff882242fcc258eeba791		 rtf-objdata-decoded RTF \objdata at offset 0x2075 2150 bytes

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