Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5032eae023119eb5…

MALICIOUS

RTF / .DOC

36.9 KB First seen: 2023-06-16
MD5: 056f5ae62038d26537b93f72dbbed514 SHA-1: f407a31aafcbaf1476853dcadd911ad25d0433ec SHA-256: 5032eae023119eb538189c2e483a1acbb4a2f0c1f56cfaed007696ec91ef0443
140 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 with a specific Equation Editor ProgID, triggering critical heuristics for exploitation. The \objupdate directive indicates an attempt to force OLE activation, which is a common method for exploiting vulnerabilities like CVE-2017-11882. The document body contains a lure to enable editing, further supporting the malicious intent. The primary goal appears to be exploiting the Equation Editor vulnerability to gain initial execution, likely for a subsequent 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_off0000417c.bin
cbc9cbcd4ddcbc91e03a9a6acf8be3f2e4806544bb6b017dee0d5742e6c04242
rtf-objdata-decoded RTF \objdata at offset 0x417C 1540 bytes