Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 21c1b0740fb8e13a…

MALICIOUS

RTF / .DOC

31.0 KB First seen: 2023-03-22
MD5: f8787a0e6b80b20bb6da5bf6def1b828 SHA-1: 2df604286909d6842c8506333db9ffc75b97753b SHA-256: 21c1b0740fb8e13a15ad3c2f26b37e0093d9acd4d426bd3661d99a4996077f4a
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1059 Command and Scripting Interpreter

The sample is an RTF document that uses an Equation Editor OLE object, a known exploit vector. The document body contains a lure, presenting itself as an academic assignment and instructing the user to 'Enable editing' to bypass security measures. This strongly suggests the document is designed to exploit a vulnerability via 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.
  • \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_off00004a47.bin
74a45b3d09ae7aa944cdaf15e65fc30b5b0bbef9e813d277b7df9bdea254334d
rtf-objdata-decoded RTF \objdata at offset 0x4A47 1967 bytes