Office (OLE) / .XLSX malware analysis — malicious · 7e87071728d1c67c

MALICIOUS

Office (OLE) / .XLSX

48.5 KB Created: 2020-10-21 08:13:35 Authoring application: Microsoft Excel

MD5: 3dd2c96309361a1805d2f7cb6a919e9f SHA-1: 05fd6590069f37913b106eb81f37c48226cc01d2 SHA-256: 7e87071728d1c67cd35d52c85150b57a93d5f0698c977c220e0b50a74cff2626

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristics indicate the presence of Excel 4.0 macros, specifically an Auto_Open defined name, which is a common technique for executing malicious code. The presence of dangerous formula APIs further supports this. The macro sheet itself contains a large amount of obfuscated data, suggesting it is designed to hide its true functionality, likely to download and execute a second-stage payload.

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` `9face49e7c278a8f0da3ae34a5725746dcd29d74fafd96e62fc039cabbe66b90`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	13240 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.