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

Static analysis result for SHA-256 514924d9abbf9396…

MALICIOUS

Office (OLE) / .XLS

215.0 KB Created: 2020-06-29 07:04:13 Authoring application: Microsoft Excel
MD5: 146cae5e7946fee5981151075d0c7d30 SHA-1: e2eeefdc9347e1f1f16b61a749a895bfe1c33d2d SHA-256: 514924d9abbf9396ff3acdccc8b4a601445f01b73fe2df49a12b18d04bca5148
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 User Execution: Malicious File T1105 Ingress Tool Transfer

The sample is an Excel (.XLS) file containing Excel 4.0 (XLM) macros. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous formula APIs to execute code upon opening. While the document body contains a large amount of of obfuscated or random-looking text, the extracted scripts are truncated and do not reveal a final reconstructed URL or command, preventing a specific family attribution.

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
a94da14594bc1ca3929dadda4320aef7f003e74705313ade063b98a619cc2d8b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 106725 bytes

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