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

Static analysis result for SHA-256 e1f178fcd7c038b4…

MALICIOUS

Office (OLE) / .XLS

54.5 KB Created: 2020-10-28 08:15:02 Authoring application: Microsoft Excel
MD5: 380447c409af41a6df78c5c509c12f2c SHA-1: c04f851ce807650bd085d2e0cbbed8e00514cba8 SHA-256: e1f178fcd7c038b40d75d637a1b8260a176d83b57328d72c152d1ebb95a8485d
180 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous functions, including a halt gate for environment evasion. The macro sheet itself contains a large amount of obfuscated text, suggesting it is designed to hide its malicious functionality. While no specific URLs or commands were extracted, the presence of Auto_Open and dangerous functions strongly suggests a malicious intent, likely to download and execute a secondary payload.

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
bc3ac781ede5084224a1dbc3f93c79c3f98f08381bafc53ce70670446a3b54d6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16628 bytes

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