Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 bb7b6c9fea213981…

MALICIOUS

RTF / .DOC

80.4 KB First seen: 2023-10-16
MD5: c44f06f0d47038f529817fe142e37b7a SHA-1: a9e82bf28436171976199de4b52cfecaaefe6937 SHA-256: bb7b6c9fea213981e2705bfac7829ca234c75ea9c78a032a862adc23c4b45e00
180 Risk Score

Malware Insights

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

The sample is an RTF document that leverages the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR heuristic. It contains an OLE object with automatic updating enabled, designed to trigger execution upon opening. The document body includes a lure instructing the user to 'Enable editing', a common tactic to bypass security measures and facilitate the execution of the embedded exploit.

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_off00003397.bin
dad102eae9f8a69aade9a407e9f40260b8ec76cdbdedf2de7900030f247c6a18
rtf-objdata-decoded RTF \objdata at offset 0x3397 1790 bytes