Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 09fbc9ef18c64027…

MALICIOUS

RTF / .DOC

32.3 KB First seen: 2023-07-05
MD5: 9cb89bef1811eba255e7b7031218a10f SHA-1: 57e58bf2ea5da5130aa375928bb366d0cabcb09f SHA-256: 09fbc9ef18c64027c5bf9b1a89d46e2561e0eabc77f3fe1e22c39244a017370a
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic

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' to view the content, which is a common tactic for macro-based malware droppers. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly suggests an attempt to exploit a known vulnerability to execute arbitrary code.

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_off00005658.bin
800ff98b5c89f886764f6b5d6974534c046c300fa22a5a68a92ebdaf506e02b5
rtf-objdata-decoded RTF \objdata at offset 0x5658 1826 bytes