Malicious RTF — malware analysis report

Static analysis result for SHA-256 8a2565ee16cf761d…

MALICIOUS

RTF

28.7 KB First seen: 2023-07-05
MD5: 524a7c0b9bd2e45a5d6c0c400067eaf3 SHA-1: 4dacc89e820e4636d73f1c1af8f6be2fe1869cff SHA-256: 8a2565ee16cf761de7b01ee51b25958c9c8b099e00196050b27bb634e53431ee
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059.005 PowerShell T1204.002 User Execution: Malicious File

The RTF document contains an OLE object with embedded data, specifically targeting the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic to bypass security measures. The presence of `RTF_EQUATION_EDITOR` and `RTF_OBJUPDATE` heuristics strongly suggests exploitation of the Equation Editor to trigger the OLE object activation, likely leading to the download and execution of 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_off00004aab.bin
64f6a3da3de3fd5d5fabfb894f109b21feb4947138382ef9fc88a06ad5ca9f08
rtf-objdata-decoded RTF \objdata at offset 0x4AAB 1744 bytes