Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 bc6fe96306eb0dcd…

MALICIOUS

RTF / .DOC

138.1 KB First seen: 2024-05-23
MD5: a19ff7526e4447064c95123087783231 SHA-1: 28cd27bb7050fb4f5534f584b83ca3be90d64ac8 SHA-256: bc6fe96306eb0dcd81bbe50db9e9996b01ca39b22efa79fce253d38532353051
160 Risk Score

Malware Insights

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

The file is an RTF document containing an embedded OLE object that exploits a vulnerability in the Microsoft Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common tactic for macro-based malware droppers. The critical RTF_EQUATION_EDITOR heuristic confirms the exploit attempt.

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_off00008f89.bin
cc10ec4d34ce942d0b381ba62e38e895745c254ed026ae6cc06827d9c9d6ef38
rtf-objdata-decoded RTF \objdata at offset 0x8F89 1540 bytes