Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 f0d3327dc670a50c…

MALICIOUS

Office (OLE) / .XLSX

17.5 KB Created: 2003-07-16 00:11:34 Authoring application: Microsoft Excel
MD5: 64eb42965349d157212c86f74da69de9 SHA-1: 1f3f2056b57c8eedcdc50412bb7620a86505e021 SHA-256: f0d3327dc670a50c85a32a63d38408657eb50e24e51763e18dfdc1be8ff45022
320 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1105 Ingress Tool Transfer

The sample contains a Workbook_Open macro that executes a function named 'Crazz'. This function attempts to save a copy of the workbook to 'c:\windows\Not2open.xls' and creates a registry file 'c:\windows\crazz.bak' to modify the 'Options6' value under 'HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Microsoft Excel' via 'regedit /s'. This indicates an attempt to establish persistence and potentially download further payloads.

Heuristics 7

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • ClamAV: Xls.Trojan.Crazz-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Crazz-1
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7e1a11b91ec0934eeada6dd71a3f8ded0208ddd0b6c15c4c15c927c19551bbe9		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 2573 bytes
Detection
ClamAV: Xls.Trojan.Crazz-1
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.

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