Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f55b29e7a1d6e7b4…

MALICIOUS

RTF / .DOC

25.3 KB First seen: 2023-01-24
MD5: 045cb870947f0903dbb4feb7bc1b8b05 SHA-1: 736088db93487ce64f05f6a967f2308eb132836d SHA-256: f55b29e7a1d6e7b4a5f7e3363fb4190cf8779f95a29de5c39f91748c7884b9f8
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample is an RTF document containing an OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The 'SE_ENABLE_LURE' heuristic indicates the document likely prompts the user to enable content, a common tactic for macro-based malware. The embedded OLE object is the primary indicator of compromise, suggesting the document's purpose is to trigger this exploit for further execution.

Heuristics 6

  • 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.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • 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 1 \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_off00004a1a.bin
e12bef76f4a03d5d1a977f9744b66e2b67bb0887de658040c01eee43eacde434		 rtf-objdata-decoded RTF \objdata at offset 0x4A1A 1956 bytes

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