Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3cadd545e00f461d…

MALICIOUS

RTF / .DOC

61.7 KB First seen: 2023-10-17
MD5: 8fbcd6bec78788ab73711987dd6350a5 SHA-1: 6519ba7f1d8af2a554e24c24cbc7a0c9a72c5af0 SHA-256: 3cadd545e00f461d514fe30ab202c0a2d71e71436db792e0c01965b1ec33bbfb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document containing OLE object data and an Equation Editor exploit, indicated by the RTF_OBJDATA, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics. The document body presents a financial audit-related lure to encourage users to enable editing, which is a common technique for malware droppers to bypass security measures. The presence of the Equation Editor exploit suggests an attempt to leverage a known vulnerability for initial execution.

Heuristics 4

  • 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
  • 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_off00002b35.bin
f12eedf0b8f9b8b865599a41fbbcc020178a6f68a123d40cdbd6c5e96184ec6b
rtf-objdata-decoded RTF \objdata at offset 0x2B35 1617 bytes