Malicious RTF — malware analysis report

Static analysis result for SHA-256 f02de4746e5703d5…

MALICIOUS

RTF

12.5 KB First seen: 2023-03-30
MD5: 7b4d587f0d734bdf9e506c89d95f1dd4 SHA-1: a872ab64815977ca7521988c16a12f8e37df40e1 SHA-256: f02de4746e5703d59c0eacf30735113567b4b4824516181693fd9b00e7623a5d
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1203 Exploitation for Client Execution

The RTF file contains critical heuristic firings indicating the exploitation of the Equation Editor vulnerability (RTF_EQUATION_EDITOR). It also contains OLE object data (RTF_OBJDATA) and is configured to automatically update and activate these objects (RTF_OBJAUTLINK, RTF_OBJUPDATE). This strongly suggests the file is designed to exploit this vulnerability to execute embedded malicious code, likely a secondary payload.

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.
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001685.bin
65e0ee7845e422153c42badc8b326263210e424ca1fb3c776a3f29ae314d5509
rtf-objdata-decoded RTF \objdata at offset 0x1685 1498 bytes