Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e9ee1749715df097…

MALICIOUS

RTF / .DOC

4.6 KB First seen: 2021-09-29
MD5: bce420bf88d20c3eae7d250445ef78e7 SHA-1: 8c1faf405eb36d73b9674f26f4aaa37521e66dd6 SHA-256: e9ee1749715df097bb4184cdc4ad0a627ba0c995147290de79f17b02d27ae10a
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains embedded OLE objects and specifically triggers the Equation Editor vulnerability. The ".objupdate" directive forces the activation of the embedded OLE object, which is likely to contain a malicious payload. This indicates an attempt to exploit the Equation Editor to gain arbitrary code execution.

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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000a2.bin
edd4b0cf33519450050b086663d4dfe505b9987f8594e44837fdcdd4f7af1eeb
rtf-objdata-decoded RTF \objdata at offset 0xA2 2101 bytes