Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 91e929f29687deac…

MALICIOUS

RTF / .DOC

169.5 KB First seen: 2023-10-25
MD5: 36a6bdf3b55abc62bf0aba5adabbfa2e SHA-1: 7346a8dc98b6e42c19086818db6b2beec6144983 SHA-256: 91e929f29687deac84a60b59e080981296ed883a3960ce00880ccbf206216afd
160 Risk Score

Malware Insights

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

The sample is an RTF document that exploits the Equation Editor vulnerability (RTF_EQUATION_EDITOR). It contains an OLE object that is likely to be activated upon opening, forcing the user to enable editing and potentially macros (SE_ENABLE_LURE). This is a common technique for delivering a second-stage payload.

Heuristics 5

  • 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_off00002d91.bin
4ee260f0e910b4912d24a214bdb96c6f487821c50cbe81281cf948da95d3d4a4
rtf-objdata-decoded RTF \objdata at offset 0x2D91 1820 bytes