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

Static analysis result for SHA-256 27ec7a12359c0da7…

MALICIOUS

Office (OLE) / .XLS

78.0 KB Created: 2023-01-26 17:22:13 Authoring application: Microsoft Excel First seen: 2023-01-27
MD5: 71be6fa63bf50f67825a08a9d9e88b0c SHA-1: c6ca3fe9d672d3324c3243c365f4a9ad3d739baa SHA-256: 27ec7a12359c0da7c2d94dc5e12e0f3939cc892b514e9d19ce653c7e71864ad8
328 Risk Score

Malware Insights

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

The file contains VBA macros, specifically a Workbook_Open event, which is designed to execute automatically when the workbook is opened. The macro utilizes the URLDownloadToFile API to download a payload from a remote source and ShellExecuteA to execute it. This indicates a downloader or droppper functionality.

Heuristics 8

  • 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-10033383-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-10033383-0
  • 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.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
e2d70b114b80571f7c9c22d6c3e7454bf564e55f9845461a50092b585e801d44		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 17981 bytes

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