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

Static analysis result for SHA-256 fa967d25a1edfc76…

MALICIOUS

Office (OLE) / .XLS

54.5 KB Created: 2020-10-28 08:15:02 Authoring application: Microsoft Excel
MD5: f1feb8d03872d302151feadb367272a6 SHA-1: 76c87634b9474e7d1a1c3def186b0d5226211063 SHA-256: fa967d25a1edfc762e45199840ff300d1f3ad4dc72bbea6672d90a577bd4de0d
180 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Critical heuristics indicate the presence of an Auto_Open macro, which is configured to execute a command via the RUN function (risky-formula=3; RUN=0). This indicates the macro is designed to run an external command upon opening. The presence of environment evasion techniques suggests an attempt to hinder analysis. The document body contains obfuscated text, which is typical for lures in macro-based attacks.

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
dd5c43c24ae1e3b4e0870bb2a95ef0d241d1d8c6d064afa764269700ddcf0af1		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16071 bytes

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