Malicious RTF — malware analysis report

Static analysis result for SHA-256 0581cf084cf7c01d…

MALICIOUS

RTF

53.0 KB First seen: 2023-08-01
MD5: bef11c74ed5d10f3f50e4fc758039348 SHA-1: 5e42cc3d55308e7c0d2e2c1d13a5ef71a8351b9a SHA-256: 0581cf084cf7c01dea29d1c44b81cfaf4a6b1441a7f5e97840317066c2593d6b
180 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object, specifically targeting the Equation Editor vulnerability, and includes a lure to enable editing. The heuristic firings indicate the use of an automatically linked OLE object that forces activation, suggesting it's designed to exploit a vulnerability and likely execute a payload. The document body provides a plausible pretext for enabling editing, aiming to bypass security measures.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off000033fb.bin
e1118aef8dd6235a9dea6032541db0768fb5cd08d9d1c72949d392cde6966f60
rtf-objdata-decoded RTF \objdata at offset 0x33FB 2072 bytes