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

Static analysis result for SHA-256 a63a94b69e30e5a4…

MALICIOUS

Office (OLE) / .XLS

474.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: b694487cfd85b3ba7f0abbda56bc1574 SHA-1: 09e51ab0a96e21aa5801952a2a1a19a78bc19b75 SHA-256: a63a94b69e30e5a4b4e5f46aa8b9380ec1e48e042e9a833a8715807d0314e8eb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The file is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The macro likely downloads and executes a second-stage payload from the embedded URL: http://cssalt.com/examples/cssalt.php. The XLM_DANGEROUS_FN heuristic firing with RUN=0 further supports the execution of external commands.

Heuristics 3

  • 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.
  • 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
ec48c34acde51fff8fc4d0086d45a1a1bc72250aa39b749e9419643eee2d6389
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 20266 bytes