Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 818d76bc4671562d…

MALICIOUS

RTF / .DOC

28.9 KB First seen: 2023-03-24
MD5: a88de09ed33f9a28c344de2f4c15c1a6 SHA-1: f203f3ddc886b9e8a2c3ce1fb34e839eec2f925e SHA-256: 818d76bc4671562df0554f11f455d99d64749a2800b52c7800108d6d3dd6602b
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1059 Command and Scripting Interpreter

The sample is an RTF document that leverages the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics. The SE_ENABLE_LURE heuristic suggests the document prompts the user to enable content, a common social engineering tactic. The embedded OLE object data is likely the exploit code, designed to achieve arbitrary code 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_off00004220.bin
23a710cedd60f119d35981bfe1bab62294796c19b626cd01db530cace2a5fe20
rtf-objdata-decoded RTF \objdata at offset 0x4220 1919 bytes