Office (OLE) / .XLSX malware analysis — malicious · 39c102840b3659b0

MALICIOUS

Office (OLE) / .XLSX

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

MD5: 1b4a53e27c7075e887093b783b485f0d SHA-1: 70ebee09c96848cf2599b25e5ba7f833b27f2a81 SHA-256: 39c102840b3659b091c93d7d6cd00099fae949d718f9e59dee703a0f73e483eb

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN in the Auto_Open macro suggests the intent is to execute arbitrary commands. This is a common technique for downloading and executing further malicious payloads.

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` `1fa89859f2ad0643c0268dabe1ccd034d4409d89839bdd182d456c2a9c9f04ef`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	7913 bytes

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