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

Static analysis result for SHA-256 dcc333c2828888bd…

MALICIOUS

Office (OLE) / .XLS

63.5 KB Created: 2020-04-28 09:07:00 Authoring application: Microsoft Excel
MD5: 29a8241d6566a4116c760f0a9bc461b5 SHA-1: 389e3e98d7c6c562f8729723136fb6435ecd9f1a SHA-256: dcc333c2828888bdcd7fbb330bc3deb709c2cc010612e634caa88bc75af05d38
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

This Excel 4.0 macro-enabled spreadsheet contains an Auto_Open macro, which is a critical indicator of malicious intent. The macro utilizes dangerous functions such as RUN and ShellExecute, and references URLDownloadToFile, suggesting it is designed to download and execute a secondary payload. The presence of these functions and the auto-execution mechanism strongly indicate a malicious downloader.

Heuristics 5

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
d6dbae05077b2289201ee506285dd349bdf66d41221a8bb1f32b36acd5f6a33c
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 24373 bytes