Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e82a2e71daee5793…

MALICIOUS

RTF / .DOC

35.6 KB First seen: 2023-05-19
MD5: 98135099e7851eae5752ab20a70ab907 SHA-1: 0b513e95b3c00895a95ffbffe467c7e7a1209d37 SHA-256: e82a2e71daee5793137e6746c8ade46e0ebba1dd4009c6a9e40355fa92071551
140 Risk Score

Malware Insights

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

The RTF document contains 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 'Enable editing'. This combination strongly suggests the file is designed to exploit the Equation Editor vulnerability to download and execute a secondary payload.

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_off00004dac.bin
f6a43db7873ab9cf18185be47481cc28f397dac3fbf2b8d4d46c73a4b8e5115f
rtf-objdata-decoded RTF \objdata at offset 0x4DAC 1515 bytes