Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 9af4cd17c159f25e…

MALICIOUS

RTF / .DOC

14.6 KB First seen: 2023-03-13
MD5: 6ce8f8b3a8399f039a1f42aa66d5007f SHA-1: ebdc4147bc3cda4e80e048f9cb0d4b21f708f97e SHA-256: 9af4cd17c159f25e21ddbceb1c7b8a31a8a2b5684e8bafb39e5e6780e6c77776
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1204.002 Malicious File T1566 Phishing T1566.001 Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is an RTF document that exploits the Equation Editor vulnerability. It contains an OLE object with ".objupdate" forcing activation, and a lure to "Enable editing" to bypass macro security. This indicates the document is designed to drop a malicious payload via the Equation Editor exploit.

Heuristics 5

  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000023a1.bin
2f4f4e69930538483b816633331fc1d4607ba0cf7a2af4ee05d765cf8817fed1
rtf-objdata-decoded RTF \objdata at offset 0x23A1 1438 bytes