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

Static analysis result for SHA-256 e029c734d6c1fc79…

MALICIOUS

Office (OLE) / .XLS

54.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: c3cd884decdd844870848e433ef444ee SHA-1: c641831e43c09b46e926dde17d3f41e3ae43ae5c SHA-256: e029c734d6c1fc79a44b4764c43ee25a40e5df7b5433db3063eaf245dffac9c6
180 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open macro. Heuristics indicate the use of dangerous formula APIs and environment evasion techniques, suggesting the macro is designed to execute arbitrary commands. The macro sheet itself contains a large amount of obfuscated data, likely to hide the malicious payload. No specific IOCs like URLs or hashes were extracted, but the presence of the Auto_Open macro and the use of dangerous functions strongly indicate malicious intent.

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
9fd5aba6679286ad7c22ffd2b10dbee42c6e4f52232a3808f93c2daf7c8feafa		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16564 bytes

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