Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8c759d98e69c502b…

MALICIOUS

RTF / .DOC

30.9 KB First seen: 2023-04-28
MD5: 50083e80d8f6c0efacba856682b74b6f SHA-1: 1a375903534ddab79afe6de8b513b1f512628c0d SHA-256: 8c759d98e69c502b7e0d875a38c86993fae325e8e0639b999eaa973400081459
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1059.005 Command and Scripting Interpreter: Visual Basic

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of \objupdate and the SE_ENABLE_LURE heuristic indicate that the document is designed to trick the user into enabling editing, which would then trigger the OLE object activation. This is a common technique for exploiting vulnerabilities like CVE-2017-11882 to execute arbitrary code.

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_off00004c9d.bin
01190bae918dc745c0ac8511c623c6fc8af742832faed07747a6551371e6c9ae
rtf-objdata-decoded RTF \objdata at offset 0x4C9D 1843 bytes