Malicious RTF — malware analysis report

Static analysis result for SHA-256 669ea7e10648928c…

MALICIOUS

RTF

46.3 KB First seen: 2023-09-07
MD5: 9753a8454818b1153caadd3e3ea6c365 SHA-1: ca7bb6712fc7c1972d4ab6d5046d4652ad33e5ec SHA-256: 669ea7e10648928c344d73f35e28f92a33702a8636be337b389145a94e065c2c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document that contains an embedded OLE object, specifically targeting a vulnerability in the Equation Editor. The \objupdate directive indicates that the OLE object will be activated automatically upon opening the document, bypassing user interaction for execution. The document body contains a lure related to financial auditing, likely to trick the user into enabling content, which would trigger the exploit.

Heuristics 4

  • 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
  • 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_off00002803.bin
5f72b598506d86cf49b63a22d39644dc1125d13804484c99a3bdc4d30e9b5c81
rtf-objdata-decoded RTF \objdata at offset 0x2803 1537 bytes