Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 01fe036a89946e0e…

MALICIOUS

RTF / .DOC

4.6 KB First seen: 2022-03-18
MD5: cb822780f5b477cc59fab91b29b2d8f0 SHA-1: bccdec50c841e2386c554aca2b9982f80bcb9d26 SHA-256: 01fe036a89946e0e2f33b99b7275b0b250b67d190725cc09e1dbb904a784e434
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains OLE objects and specifically triggers the Equation Editor vulnerability CVE-2017-11882. This vulnerability allows for the execution of arbitrary code when the embedded OLE object is activated. The presence of ".objupdate" and "EqUaTioN.3" further confirms the exploitation attempt.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000b1.bin
be8fdba784d03f68f56d58609681a3a47fb57da34e21c7cbabb0d47477dcba0e
rtf-objdata-decoded RTF \objdata at offset 0xB1 2031 bytes