Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e74e69598f5855a0…

MALICIOUS

RTF / .DOC

37.8 KB First seen: 2023-02-02
MD5: 87fff477c26046802651bc15d96443db SHA-1: 68b90604e68e2598fc498ba8bfae0ddc353f4c21 SHA-256: e74e69598f5855a03d476602cd4de3bb4df94898c3659519c1ad31e70df12f28
200 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', a common tactic for macro-based malware. The embedded OLE object is specifically flagged as related to CVE-2017-11882, indicating a high likelihood of exploitation for initial access or payload delivery.

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.
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off00005229.bin
23906016ea8eac142622de55f99417286de78169282624c93d08989d3cb91620		 rtf-objdata-decoded RTF \objdata at offset 0x5229 1705 bytes

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