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

Static analysis result for SHA-256 5d8a8078fbef2e99…

MALICIOUS

Office (OLE) / .XLSX

227.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 3c975c07ab0a8bc40e3f32236c5c1385 SHA-1: 8e164247f5c0069d7da200de5e3bc7c2178d518c SHA-256: 5d8a8078fbef2e99ec4c1ca13113a787ba2bc6701496d4185f996e652b3a3005
180 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro designed to execute automatically. The document body attempts to socially engineer the user into enabling macros by claiming it was created online and requires content enablement. The presence of an Auto_Open macro and environment evasion techniques indicates a malicious intent to execute arbitrary code.

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
e802c872d30a723662d7a10ddd4ee0cf542b0eb9f3ab2ee41c1c759f2ca8de03
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 327176 bytes