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

Static analysis result for SHA-256 c9204ab39826146e…

MALICIOUS

Office (OLE) / .XLSX

233.0 KB Created: 2020-09-07 13:04:09 Authoring application: Microsoft Excel
MD5: c6cec456b38bed7c3047d69c00603246 SHA-1: a4abfec295012a45ff1aa6905154640399139414 SHA-256: c9204ab39826146ee9f42aa0ae401375c93145b147f8427cce35e42e54786652
180 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro sheet containing an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The document body presents a social engineering lure to enable content. The presence of the Auto_Open macro and the use of dangerous formula APIs indicate the intent to download and execute a second-stage 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
7f8404fa1ad2c07116860f4a7666aee9e5f8a12c46042287990c4b832e003876
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 336274 bytes