Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7b37fe400a620d51…

MALICIOUS

RTF / .DOC

31.4 KB First seen: 2023-03-29
MD5: 424e6097a9af68af2c94f82e2f55ccda SHA-1: 91e96e5eb1a38d4e2b78e7e9295d6266c91a1047 SHA-256: 7b37fe400a620d514159c6ca8dd489f84a43f955d0ab4ada54a6ea541ff2a399
160 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 OLE object with a split Equation Editor ProgID, indicating an attempt to exploit the Equation Editor vulnerability. The document also contains a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. The presence of these elements strongly suggests the document is designed to exploit this vulnerability and execute a malicious payload upon user interaction.

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_off00004722.bin
66603fbd68dc6cc891b4359fdf4a6ad44c49030e70ec19f1b289a8f28c03becd
rtf-objdata-decoded RTF \objdata at offset 0x4722 1977 bytes