Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 00cd6d29e6142539…

MALICIOUS

RTF / .DOC

79.9 KB First seen: 2023-09-19
MD5: cdcd0d063bffaab68a216c729f44acfa SHA-1: 49cb0211c0b6f7fe3138c0851f38780dc4f1b8b7 SHA-256: 00cd6d29e61425391c4bc712d76d5856c7d1ab3c406996d443456160d3efe3d4
140 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object with a split Equation Editor ProgID, indicating an attempt to exploit CVE-2017-11882. The \objupdate directive forces OLE activation, and the document body contains a lure instructing the user to 'Enable editing'. This combination strongly suggests a malicious document designed to exploit the Equation Editor vulnerability to gain initial access and likely download a second-stage 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_off0000398c.bin
e5aaa3f935bc85f256076fe8644e6356df440dd5e6881af583e675265393b4a1
rtf-objdata-decoded RTF \objdata at offset 0x398C 1818 bytes