Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8087f52a641c5b10…

MALICIOUS

RTF / .DOC

25.9 KB First seen: 2023-03-20
MD5: 455aafe9f2d7bfc59a2debde86d8a794 SHA-1: 45526679f277c49dcb394f7edd95920a75884f55 SHA-256: 8087f52a641c5b1089c76a2ec004ce78d9bfb08bedbc5ce68ef6ddfbd5d19c4f
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object with a ProgID indicative of the Equation Editor vulnerability (CVE-2017-11882). Heuristics indicate that the OLE object is automatically linked and updated, suggesting an attempt to trigger an exploit upon opening. The document body contains a lure instructing the user to 'Enable editing', a common tactic to bypass macro security and activate embedded exploits.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00004563.bin
17382b2a45994168a9c3ac4c41aa02df0d64450345f9c41f218425c8fdaf4b14
rtf-objdata-decoded RTF \objdata at offset 0x4563 1575 bytes