Malicious RTF — malware analysis report

Static analysis result for SHA-256 867bedbac9a7a430…

MALICIOUS

RTF

39.4 KB First seen: 2023-07-14
MD5: 76888ed7d5292cc0199965507ea9a5c3 SHA-1: 53a27b90c3f6603a738ee5ffb2c2ed9d9cd2c0cc SHA-256: 867bedbac9a7a430af4558f4825f80e13ae8b38eaa1dc27863bc7a7491e9ad32
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a split Equation Editor ProgID, a known vulnerability exploited by malware. The ".objupdate" directive indicates that the OLE object will be activated automatically upon opening. The document body includes a lure to "Enable editing", common for macro-based malware. The primary attack vector appears to be exploiting the Equation Editor vulnerability to achieve code execution.

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_off000041dc.bin
5399edd262659782a84684f0f1e70272b231a8ab6897e479e08f90164e14cecf
rtf-objdata-decoded RTF \objdata at offset 0x41DC 1883 bytes