Malicious RTF — malware analysis report

Static analysis result for SHA-256 0cd55b0619f944c1…

MALICIOUS

RTF

35.4 KB First seen: 2023-05-18
MD5: e889b9696cdf30dda6e06dee81511ad2 SHA-1: 20ab91800b07d563acf8431f9664f669e8817a63 SHA-256: 0cd55b0619f944c164f3ac20fcc4ed608fbdf5078360a2b94a6306d977f6b141
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1059 Command and Scripting Interpreter T1566 Phishing

The RTF file contains an embedded OLE object with a split Equation Editor ProgID, indicating an attempt to exploit CVE-2017-11882. The \objupdate directive further suggests that the OLE object is intended to be activated automatically. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware droppers. The primary goal appears to be the execution of a second-stage payload via the Equation Editor vulnerability.

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_off0000483b.bin
ab580c60f0d93f177b891d6ee5860410b4b7ed94d33c05fa326a183bd91fc7d9
rtf-objdata-decoded RTF \objdata at offset 0x483B 1720 bytes