Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1646017b8052c3ea…

MALICIOUS

RTF / .DOC

39.0 KB First seen: 2023-07-19
MD5: cc47323a812b42250d34573c4b9f12e0 SHA-1: 2af65a3a53f0a39fe33c17aa43698c2d1a0bee61 SHA-256: 1646017b8052c3ea33881beeb6c7e7755567eaa49c4eb2df8e7d89496af01f7d
160 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 containing 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_OBJUPDATE and RTF_EQUATION_EDITOR heuristics strongly suggests an attempt to exploit this vulnerability, likely leading to the download and execution of a secondary payload.

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_off0000408c.bin
8550ccf7fd7fff6f10d94f57e4094c06594a0f1704c9a956beff96514ebee9d7
rtf-objdata-decoded RTF \objdata at offset 0x408C 1799 bytes