Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b30d6e23a319a4bd…

MALICIOUS

RTF / .DOC

23.5 KB First seen: 2022-11-30
MD5: 8e59a5a134a38809a6c7bee8b3b9cd9b SHA-1: 8331a36576b4fed98dfc4ab7297f1221cf0a54f9 SHA-256: b30d6e23a319a4bd93eb4a344166d885b71de3ece98bcc12e9f67c3e25a8214b
220 Risk Score

Malware Insights

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

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability through an embedded Equation Editor OLE object. The document body contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware. The critical heuristic firing for CVE_2017_11882_ACTIVATION_RELATED confirms the exploitation attempt, which is designed to execute a secondary payload.

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_off000044fd.bin
9eee39783c09b323ea4680cd4cf6f45a7582b0ac5185ddbd5f1bbf5d931d46c1		 rtf-objdata-decoded RTF \objdata at offset 0x44FD 1820 bytes

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