Malicious RTF — malware analysis report

Static analysis result for SHA-256 4f90151cd4135476…

MALICIOUS

RTF

34.8 KB First seen: 2023-07-04
MD5: 5321abc2b59da0447bf1e9ea2505e4d4 SHA-1: a8aff5e665051c9365c47a33888cc4ea0b7f1a25 SHA-256: 4f90151cd41354763817576c37b92b3b294ebe62f2682477bf9595ab17c0461a
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File T1059.005 PowerShell

The RTF document contains OLE object data and specifically triggers heuristics related to Equation Editor vulnerabilities and automatic OLE activation. The document body includes a lure instructing the user to 'Enable editing', a common tactic for macro-based malware or exploits. The presence of `RTF_EQUATION_EDITOR` strongly suggests an attempt to exploit the Equation Editor vulnerability, likely to download and execute a secondary 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_off00004f3e.bin
3a750637f089a20e954069ed06a28cdfbe01704d872c66bbd1007552106241f7
rtf-objdata-decoded RTF \objdata at offset 0x4F3E 1624 bytes