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

Static analysis result for SHA-256 9e41f526fb6d6e27…

MALICIOUS

Office (OLE) / .XLS

53.5 KB Created: 2020-10-26 09:32:25 Authoring application: Microsoft Excel
MD5: af514c202b728469af8df1d6095a0c61 SHA-1: bd492276b6a4e7c68145bcc92ba38c78b822251e SHA-256: 9e41f526fb6d6e2736c3bc4b974b1e9539c2a804c7a5ebf14025d7d495fcd010
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1566.001 Spearphishing Attachment T1059.001 PowerShell

The file is an Excel 4.0 (XLM) macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that uses dangerous functions, including 'RUN', and employs environment evasion techniques. While the specific payload is not directly visible, the presence of an Auto_Open macro strongly suggests an intent to execute arbitrary code upon opening, typical of a downloader or initial access mechanism. No specific IOCs were extracted from the macro content itself.

Heuristics 4

  • 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.
  • XLM Auto_Open environment-evasion HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • 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
627f3c74d3ada090c05afc84186281107df47e932e8c6435b094a037684348a9		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 15543 bytes

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