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

Static analysis result for SHA-256 f57a3f475e7eadf3…

MALICIOUS

Office (OLE) / .XLSX

173.0 KB Created: 2021-10-19 23:15:33 Authoring application: Microsoft Excel
MD5: 86dd580df1bbb186f9e99983468fece2 SHA-1: 9886764cac21fa8421d8ab2c371d9a6fa4ad8aeb SHA-256: f57a3f475e7eadf3c090159567858ca5f13323d32300214a9032e44105baa8b3
390 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer T1059.001 PowerShell

The critical heuristic OLE_VBA_DOWNLOAD indicates the presence of URLDownloadToFile within VBA macros. This is further supported by the SC_STR_URLDOWNLOAD heuristic. The Workbook_Open macro (OLE_VBA_WBOPEN) is configured to execute automatically, and the SE_ENABLE_LURE heuristic confirms a user-facing prompt to enable macros. The script uses ShellExecuteA and URLDownloadToFileA APIs to download and execute a second-stage payload, as indicated by the critical ClamAV detection and the SC_STR_SHELLEXEC heuristic.

Heuristics 11

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in VBA
  • ClamAV: Xls.Malware.Valyria-10028013-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-10028013-0
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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
  • 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
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/photoshop/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/tiff/1.0/
    • http://ns.adobe.com/exif/1.0/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
372a628ef609495b14a83f54c61d7822e41cb3fffa2f5d08a2e00993b3d5504f		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 15191 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s). Carved artifact contains 16 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.

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