Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f2c01a2894fc6f41…

MALICIOUS

RTF / .DOC

37.3 KB First seen: 2023-05-16
MD5: f51150f6c694ce9b88e003676fbf7339 SHA-1: f574893c88c7b4571bca8a77776d1e6175e306fc SHA-256: f2c01a2894fc6f41a5277342ff771175ff1860fdda3b9e913e18f0d3489ba067
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 PowerShell

The sample is an RTF document containing an embedded OLE object that leverages a known vulnerability in the Equation Editor. The presence of RTF_OBJUPDATE and SE_ENABLE_LURE heuristics indicates the document is designed to trick the user into enabling content, which then triggers the exploitation of the Equation Editor vulnerability. This is a common technique for delivering secondary payloads.

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_off00005142.bin
aad6d11c51c286a2fa0badfc323801c2b45cef3d9ccdc25d420295360605e634
rtf-objdata-decoded RTF \objdata at offset 0x5142 1565 bytes