Office (OLE) / .XLSX malware analysis — malicious · 830809b4cc139264

MALICIOUS

Office (OLE) / .XLSX

41.5 KB Created: 2020-09-28 00:53:43 Authoring application: Microsoft Excel

MD5: bc3646cfc6dfabb1a860f0c4a6c19702 SHA-1: 0e678d31c29fe14f081ec1d4f0ccb54be4edda28 SHA-256: 830809b4cc139264161c5da86194a56cee9de52c6af2dc7df0db32de0427a010

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 with an Auto_Open defined name, which is a known method for executing malicious code. The macro sheet contains a dangerous formula API, specifically the RUN function, suggesting it's designed to execute arbitrary commands. The presence of an Auto_Open entry strongly implies an attempt at automatic execution upon opening the document.

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` `d837f04d969527e349b35f90c4e98117dd009821ef16580d53a3b89317c2947b`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	8116 bytes

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