Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a6b26dad5f3e39e9…

MALICIOUS

RTF / .DOC

76.7 KB First seen: 2023-01-19
MD5: 1ad9caa259cdad25112cc9ed73806f98 SHA-1: f0b29a43b0c1553e477bc62522d8e38c793c1497 SHA-256: a6b26dad5f3e39e9379ff8ccb27c9815d5f3a2740581613a057d20d0db72da86
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 PowerShell

The sample is an RTF document that contains OLE object data and specifically targets the Equation Editor vulnerability. The \objupdate directive indicates that the embedded OLE object will be activated upon opening, which is a common technique for exploiting client-side vulnerabilities. The document body contains a lure to enable editing, further supporting its role as a malicious dropper.

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_off00005aff.bin
18763547954961613593af24dc7d77b377f3adaf5df80fa1d9ff35f96b4d0ea3
rtf-objdata-decoded RTF \objdata at offset 0x5AFF 1436 bytes