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

Static analysis result for SHA-256 e3a57dc258b1a71a…

MALICIOUS

Office (OLE) / .XLS

54.0 KB Created: 2020-10-28 08:15:02 Authoring application: Microsoft Excel
MD5: d4fb0340987c5ef4048dd9c941976d07 SHA-1: ab773cb01d337ce99987911f2f402eccc2b8409f SHA-256: e3a57dc258b1a71aad41fa00e39d4c0b41c8d8d2a107eea73f2e6c1894d7c754
180 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous formula APIs and includes environment evasion checks. This suggests the macro is designed to execute malicious code upon opening, likely to download and run a secondary payload. The extensive obfuscated text in the document body further supports a malicious intent, possibly to bypass detection or mislead the user.

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
9cfd01f2db3eb72a3acf8f0b903a3cff288fafbc69fbf83460c65613d83b636d		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16007 bytes

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