Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f41ea364ab7098e4…

MALICIOUS

RTF / .DOC

12.0 KB First seen: 2022-04-12
MD5: 68a83e9af97152d32792dc67cd6c65f3 SHA-1: 725d75f04c4a6e84df3110b816ccdf541d3a3886 SHA-256: f41ea364ab7098e4aa3b20a468604f0e7ce447d96fa05fa13400196d413a7253
121 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that contains embedded OLE object data and specifically triggers the Equation Editor vulnerability. The \objupdate directive forces OLE activation, indicating an attempt to exploit the embedded object. This is a common technique for delivering second-stage payloads, although no specific payload or URL was directly extracted from this sample. The critical heuristic firing for RTF_EQUATION_EDITOR strongly suggests exploitation of CVE-2017-11882.

Heuristics 3

  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00002099.bin
e492d2f033e0f7732cb330b17e5816c8f2220a07efb4828eee21db81b7597289
rtf-objdata-decoded RTF \objdata at offset 0x2099 1774 bytes