Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 caa00114ad5c586f…

MALICIOUS

RTF / .DOC

65.3 KB First seen: 2023-09-26
MD5: f64d55ed5e5fb9199e547e5803e14a7b SHA-1: 1e19a10741b9f8421c2a2d26da1a5f3afd354912 SHA-256: caa00114ad5c586facec5402cd62993b4749aa34f9dbbd01268f3ea3fb00bedf
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 exploits the Equation Editor vulnerability. It contains an OLE object and an \objupdate directive, indicating an attempt to activate embedded content. The document body provides a lure, instructing the user to 'click Enable editing', which is a common tactic for macro-based malware delivery.

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_off000029cd.bin
30f9bd3904997740d08616fc830fd3fa4b42655422c98c71c027416a9ce3e9e2
rtf-objdata-decoded RTF \objdata at offset 0x29CD 1490 bytes