Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 691f52116daeff38…

MALICIOUS

RTF / .DOC

30.6 KB First seen: 2023-05-15
MD5: 935cdc2a55d5b8808d4c56ae2e753946 SHA-1: 3995212898cd19eca670bae969ae2f0d6b8d9f79 SHA-256: 691f52116daeff38b71050cd3bd4aa886c7a3d2351cc196a6d78b28efa80cb07
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Service Execution: Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits a known vulnerability in Microsoft Equation Editor. The presence of \objupdate indicates an attempt to force OLE activation, and the SE_ENABLE_LURE heuristic suggests the document prompts the user to enable content. This combination strongly indicates a malicious document designed to exploit the Equation Editor vulnerability for initial execution, likely leading to a secondary payload download.

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_off000044ea.bin
9e6216b74e6aef2c8607d8849d1a5e604f04c932f801eebfe456f646a70be1bb
rtf-objdata-decoded RTF \objdata at offset 0x44EA 1270 bytes