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

Static analysis result for SHA-256 1b451bedd7003c44…

MALICIOUS

Office (OLE) / .XLS

194.5 KB Created: 2020-07-01 23:17:53 Authoring application: Microsoft Excel
MD5: 559c2596f452c8a58adb3d514510c97a SHA-1: cc747e956cee63c9fe7ac4b01cedd90f340063ab SHA-256: 1b451bedd7003c4400d3803977d3940d9b98b8defaf30b6ef549843425435126
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open macro, which is a known technique for executing malicious code. The heuristics indicate the use of dangerous formula APIs like RUN, suggesting the macro is designed to execute external commands. The presence of environment evasion techniques further supports malicious intent. While no specific URLs or hashes were extracted, the macro's functionality strongly implies it acts as a downloader for further malicious activity.

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 close gate critical OLE_XLM_ENVIRONMENT_EVASION_CLOSE
    Excel 4.0 macro sheet auto-executes environment checks with GET.WORKSPACE / GET.WINDOW, then shows a fake corruption/error message and closes the workbook when the host fails those checks. This is a malware sandbox-evasion pattern, even when the later payload stage is hidden behind obfuscated defined-name flow.
  • 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
82a09520eea29514020c8e635f9c6c9457df9c7fc402ec78768af83bc89f4fbc		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 74177 bytes

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