Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e4bbff1ae7b23af0…

MALICIOUS

RTF / .DOC

166.7 KB First seen: 2023-05-26
MD5: 392e36a882dc396675f0320d9dd3557e SHA-1: 0b6f4386d4be0bdfae7ef2a38484fd80fb6199b3 SHA-256: e4bbff1ae7b23af022c680cf2066c974093f16086d48b153521350c51d4c729d
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an RTF document that contains OLE object data and specifically targets the Equation Editor vulnerability. The ".objupdate" heuristic indicates that the embedded OLE object is automatically activated upon opening the document, leading to the exploitation of the Equation Editor. This is a common technique for delivering secondary payloads.

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_off000012be.bin
29fe68489688ffc0b2d198a7f9f63b00aebc79fae3859b6820877367d0c9cef8
rtf-objdata-decoded RTF \objdata at offset 0x12BE 46317 bytes