Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c8e257489871793f…

MALICIOUS

RTF / .DOC

29.6 KB First seen: 2022-11-18
MD5: 103735a5f9d3cdcb35b96d1e2d821b49 SHA-1: e130c51239f7cb3eeeb4b431f89a3960e86490f6 SHA-256: c8e257489871793f4d6dcc324a0812d949ebfdf12893953bb7a55070c67138cc
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059.005 PowerShell T1204.002 User Execution: Malicious File

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic to bypass security measures. The presence of RTF_OBJDATA, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly suggests an exploit attempt via the Equation Editor. The SE_ENABLE_LURE heuristic further confirms the social engineering aspect to trick the user into activating 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_off00005967.bin
abbcca79b1f59136e89804f8c3c4c0283698ef1615c0067b1564b8f359a17898
rtf-objdata-decoded RTF \objdata at offset 0x5967 1661 bytes