Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f4b2683cb85506c0…

MALICIOUS

RTF / .DOC

119.8 KB First seen: 2023-07-05
MD5: 91ac731fae3c6e874267188c9892cabb SHA-1: ddcc9dc0990575d6a78bff10c8d1b2981ab23809 SHA-256: f4b2683cb85506c0d99935f42241f32053bade36fc7d5d13d3317a690a54e66a
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell T1204.002 Malicious File

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The \objupdate directive forces the activation of this object, leading to code execution. This is a common technique for delivering secondary payloads, although no specific payload or download URL was directly extracted from this sample.

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 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000015c3.bin
04e24ff8af7df06bd995e6f5516c7ce8f393dded55e62cc1d09c4e5be649ab0d
rtf-objdata-decoded RTF \objdata at offset 0x15C3 36167 bytes