Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 266f8edb586d3e91…

MALICIOUS

RTF / .DOC

61.2 KB First seen: 2023-09-18
MD5: 82d0358256005a69535d209d464d6184 SHA-1: 9b5d3e8dd5e2a12ada5b66d60103fac30af32698 SHA-256: 266f8edb586d3e919d51a58d65d20eecae961acb8b7005b2e9d011cd73e630e0
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The file is an RTF document containing an embedded OLE object that exploits a known vulnerability in the Microsoft Equation Editor. The document body includes a lure instructing the user to 'click Enable editing', which is a common tactic to bypass security measures and trigger the exploit. The exploit likely leads to the download and execution of a second-stage 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.
  • 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_off00003b17.bin
e1a530054f2cd97e8afd01fd80f000e8338aecf23755143a440cf95a9e8be174
rtf-objdata-decoded RTF \objdata at offset 0x3B17 1635 bytes