Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 999a7fd725845db4…

MALICIOUS

RTF / .DOC

7.9 KB First seen: 2022-12-08
MD5: d22e30833c84c880d583e54b32c1dbef SHA-1: 2dc1c5ae3f1011d1b45d143ef66bcbfb82ff1abe SHA-256: 999a7fd725845db4d0fe8d96dfdbf3d8fc168899a2c86cb84318f397baa198cd
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 the Equation Editor vulnerability (CVE-2017-11882). The document body contains a lure instructing the user to enable editing and content, which is a common technique for macro-based malware delivery. The embedded OLE object's class is identified as 'eQUAtIOn.3', directly indicating the exploit vector.

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_off00000eed.bin
dd6e8fbae5d43da28b1bc872dbdd8b2561aff0ed8074d19978bcd1b3dc7b8194		 rtf-objdata-decoded RTF \objdata at offset 0xEED 2099 bytes

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