Malicious RTF — malware analysis report

Static analysis result for SHA-256 c1a9f1091c27198c…

MALICIOUS

RTF

39.9 KB First seen: 2023-07-18
MD5: 730041eb0f81098b8da5228bedd17a82 SHA-1: f869873a37ddae8ada58083ceb2de16ab312e250 SHA-256: c1a9f1091c27198c7ff349c330a6db20e50ca2c2e7c67986cc6f646b736bfb61
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The RTF document contains a lure instructing the user to 'Enable editing' to view its content. It also contains embedded OLE object data and specifically triggers heuristics for the Microsoft Equation Editor vulnerability (RTF_EQUATION_EDITOR). This indicates the document is designed to exploit this vulnerability upon user interaction, likely leading to the execution of a malicious payload.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off000048fc.bin
b3c7d35ee844f2ff7c8a0c3169a45310fc526e31d796bdc0092289776e6ebbe6
rtf-objdata-decoded RTF \objdata at offset 0x48FC 1668 bytes