Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 76a03acbe7e80c8b…

MALICIOUS

RTF / .DOC

85.4 KB First seen: 2023-10-23
MD5: b361cb23f35219b358e8bec2c6f8fe37 SHA-1: ba3cbee4cb061a00d3607ee54ee48213ebd67513 SHA-256: 76a03acbe7e80c8b866720ce7850a4c187e5cf56bbe71b5ca9b402b7f798df13
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic

The file is an RTF document containing an embedded OLE object with a split Equation Editor ProgID, indicating an attempt to exploit a known vulnerability. The \objupdate directive forces OLE activation, and the document body contains a lure instructing the user to 'click Enable editing'. This combination strongly suggests the file is designed to exploit the Equation Editor vulnerability to execute malicious code, likely a downloader.

Heuristics 4

  • 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
  • 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_off00003e5c.bin
975fc1de5879778ca914a6f9fddd0ce1958ca124f074365d93fbcb9d7fb7a6f3
rtf-objdata-decoded RTF \objdata at offset 0x3E5C 1507 bytes