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

Static analysis result for SHA-256 d0f17fecc5d2ffd2…

MALICIOUS

Office (OLE) / .XLS

54.0 KB Created: 2020-10-28 08:15:02 Authoring application: Microsoft Excel
MD5: f558e81f9b83fd8b8eb5750499355fbe SHA-1: d4c2eae9d37f7922e8dbe05c7822b1f6c9cb2902 SHA-256: d0f17fecc5d2ffd2aa542ae19f2e5e7e46e9d00161b6e4859c5c9d8a4836ee9b
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications 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 upon opening the workbook. The heuristics indicate the use of dangerous formula APIs and an environment-evasion halt gate, suggesting an attempt to run arbitrary commands. While no specific URLs or hashes were extracted, the presence of the Auto_Open macro strongly implies the intent 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
b7f9f2839d56f8fdeff6b23a86c8beb28313c35feb5f87104845b2d3ce76ca57		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16129 bytes

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