Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 355622a12a5c9d9b…

MALICIOUS

RTF / .DOC

36.2 KB First seen: 2023-02-15
MD5: 058aa1c034321b842ea830649a97c720 SHA-1: 98a84c8e175ae0c1a1f8553ef56dc5ec3901e255 SHA-256: 355622a12a5c9d9b18501fad1472ec771faeb2b6a05af91d3557ac8127d39e46
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document that contains an embedded OLE object with a specific Equation Editor ProgID, indicating an attempt to exploit a known vulnerability. The \objupdate directive forces OLE activation, and the document body contains a lure to enable editing, suggesting it's designed to trick the user into triggering the exploit. The exploit likely leads to the execution of a secondary payload, though no specific details of that payload were extracted.

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_off00004f9e.bin
76184443f28ee0e77cf9993be2967517919d028a3eb991c5dc31e0fd1fc07964
rtf-objdata-decoded RTF \objdata at offset 0x4F9E 2099 bytes