Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1f12508822b30e1d…

MALICIOUS

RTF / .DOC

12.8 KB First seen: 2023-03-06
MD5: 74388b1571594dcd616538347f335bd0 SHA-1: 894116948a21eac51f42f11d66fe516813cf29c7 SHA-256: 1f12508822b30e1dd04d9e8b91e776c5dde66c483d07ce9ffd714138c91ccf48
120 Risk Score

Malware Insights

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

The sample is an RTF document that contains OLE object data and specifically targets the Equation Editor vulnerability. The presence of \objdata and \objupdate directives strongly suggests exploitation of a known vulnerability to trigger the execution of embedded malicious content. The decoded OLE object, objdata_00_off00001ad7.bin, is the primary artifact of this exploit.

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_off00001ad7.bin
4ece0e7d581da1f536f61dc6e7ea8b9b6c268d65720e73553f83d31a5483b0fd
rtf-objdata-decoded RTF \objdata at offset 0x1AD7 1294 bytes