Malicious RTF — malware analysis report

Static analysis result for SHA-256 1d8b6b8d9edc7442…

MALICIOUS

RTF

72.7 KB First seen: 2023-08-14
MD5: 2ee309cea90f3f32e4a7c36c33615aa5 SHA-1: 9eca5b1315220d1ca470290f9a6e17f633ee1017 SHA-256: 1d8b6b8d9edc7442f293f31f633e9e3701a91fcae93bd4b5f3468c6f6595fd4c
160 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object, 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 and trigger the exploit. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly indicates an attempt to exploit this known vulnerability.

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_off00003b41.bin
859ea2cceb2af12a483d86315477295dc49b86fc17a81850c27aa47736e0e242
rtf-objdata-decoded RTF \objdata at offset 0x3B41 1419 bytes