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

Static analysis result for SHA-256 638b9285176c5b9f…

MALICIOUS

Office (OLE) / .XLS

54.0 KB Created: 2020-10-28 08:15:02 Authoring application: Microsoft Excel
MD5: dcc23e22dfb171c9b4367ad5da4dd6bb SHA-1: dad1e5320874cce65bea82159f11c0cf1331befc SHA-256: 638b9285176c5b9f541eb705dd4bf2ef68eddc7b6e67f77c081cc38460d0be89
180 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code within older Excel versions. The presence of environment evasion techniques and dangerous formula APIs like RUN indicates an attempt to execute arbitrary commands. While no specific URLs or hashes were extracted, the Auto_Open macro itself is the primary indicator of malicious intent, likely serving as a downloader or initial execution vector.

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
7ea2cf740bbfd687699d3e67f7781beab2846362fe3f32438c8fcd9b6b79b8bc		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16610 bytes

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