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

Static analysis result for SHA-256 00352c70a741102e…

MALICIOUS

Office (OLE) / .XLS

53.5 KB Created: 2020-10-28 08:15:02 Authoring application: Microsoft Excel
MD5: 0c6451ac5008b578fa04b90ca72fd7f8 SHA-1: a46cc17417793cbece5271e4393891536aa41b30 SHA-256: 00352c70a741102eda8b008620892f5c9e9e54ceac52e0b88540ed34f382fa56
180 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 (XLM) macros, specifically an Auto_Open macro. This macro is designed to execute automatically when the file is opened, and it utilizes dangerous formula APIs and environment evasion techniques. The presence of an Auto_Open function indicates an attempt to run arbitrary code, 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
c84d1766653ad59e0662fd22ff0f6558b983f80a977d59cfac00d321b8691a84		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16422 bytes

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