Office (OLE) / .XLSX malware analysis — malicious · 64ec57d1854b91ad

MALICIOUS

Office (OLE) / .XLSX

77.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-23

MD5: 34597d8cd94d65644eb182dc358a74b1 SHA-1: be07d43faae5d4ad583081c4b50deabb4d8ff206 SHA-256: 64ec57d1854b91ad1484d29007972bb8043d773368b7b4656b3e4cf41b3eddbb

140 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 technique for executing malicious code. The macros are configured to download and execute a payload from one of the provided URLs, indicating a downloader or droppper functionality. The presence of an Auto_Open entry and the use of dangerous formula APIs strongly suggest malicious intent.

Heuristics 3

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.
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.

Filename	Kind	Source	Size
`xlm_macros.txt` `2ca0966e93dacad101ceb18f4d58731b5432892fe851526f2fda59486181312c`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	7325 bytes

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