Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a5d4b476454e677e…

MALICIOUS

RTF / .DOC

33.2 KB First seen: 2023-04-17
MD5: 186fd78214185239a926ac7f877a73f8 SHA-1: 90b94695be52733d034099009be2559a11a9ac21 SHA-256: a5d4b476454e677ed8cdb3ae83a93a5f3053876e64f4bae4b99b26cbbe345de2
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059 Command and Scripting Interpreter

The RTF document contains an embedded OLE object with a ProgID indicating an Equation Editor exploit, and an objupdate directive to force activation. The document body includes a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. This combination strongly suggests an exploit targeting the Equation Editor vulnerability 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_off000040de.bin
b30f51c51e3450d0d856faea3d6c2eb57e4ed8e1fb73ec5519ea03877d2a79c5
rtf-objdata-decoded RTF \objdata at offset 0x40DE 1648 bytes