Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 da3b69ceb1129208…

MALICIOUS

RTF / .DOC

30.5 KB First seen: 2023-06-09
MD5: 49e7854bcfc4316d396cf9b2dbcc0da4 SHA-1: e3380f03095e3271d20282206c23b169a34c249d SHA-256: da3b69ceb1129208e8a71301c40044a3263e88caf9884588f1d09d0b549b0140
180 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits a known vulnerability in Microsoft Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common technique to bypass macro security. The exploitation of Equation Editor suggests the document is designed to download and execute 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_off00004ad4.bin
bbf8ccae9877adbf2fe08c2addd75149a09b608525f98899edb973613e3831f7
rtf-objdata-decoded RTF \objdata at offset 0x4AD4 1541 bytes