Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5bd775f80d1f0705…

MALICIOUS

RTF / .DOC

64.3 KB First seen: 2023-09-12
MD5: 71c027214c3ac54535bfabd21ab46403 SHA-1: 9d51217a12f11bdb7c4ba19172217a58fdae3b93 SHA-256: 5bd775f80d1f0705fc9ebe8a61bc517840f33ba8ce5a72e3116752bd832013c8
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1204.002 Malicious File T1566 Phishing T1566.001 Spearphishing Attachment T1059 Command and Scripting Interpreter T1059.005 Visual Basic

The sample is an RTF document that leverages OLE object embedding, specifically targeting the Equation Editor vulnerability. The document body contains a lure related to financial audits, instructing the user to 'click Enable editing'. This combination strongly suggests an attempt to exploit the Equation Editor to execute 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_off00003bd4.bin
385c3020218089ad6dbe279244f17c9a3753bcec418841037de49892e175dd04
rtf-objdata-decoded RTF \objdata at offset 0x3BD4 1963 bytes