Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e90dda2a334177b5…

MALICIOUS

RTF / .DOC

24.4 KB First seen: 2022-11-17
MD5: 8b703eb9957899299b46034309b46cc9 SHA-1: c1d1c89c11e8d9a4dfbd326fa234358b02cd745b SHA-256: e90dda2a334177b57b5580c8927c1d40bd63566797e66258f0d09b972ee1cd36
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 containing an embedded OLE object that exploits a known vulnerability in the Microsoft Equation Editor (CVE-2017-11882). The presence of \objupdate indicates that the exploit is designed to automatically activate upon opening. The document also contains a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. The primary goal is likely to execute a secondary payload.

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_off00004208.bin
038cca5418315883d40cf9a9635c917c265f1f84d6a451b43bfca1fc2e51d5ad
rtf-objdata-decoded RTF \objdata at offset 0x4208 1788 bytes