Office (OLE) malware analysis — malicious · b2159f5f67524043

MALICIOUS

Office (OLE)

411.0 KB Created: 2019-10-22 07:10:34 Authoring application: Microsoft Excel

MD5: b868ef8972b158c96b414662ed2bf51d SHA-1: 6823ae4dd686422f4716c6a81a496c9b8ee37906 SHA-256: b2159f5f6752404355be70f1b882482c9996f0c4e809b565a1b1ce8705348d88

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. This macro is configured to execute a command, indicated by the presence of 'L.exe' and the command line 'c:\mess.com&start mess.com'. The URL 'ww.google.com/test.com' is also present, suggesting it may be involved in the payload delivery. The use of XLM macros for arbitrary command execution is a common technique for initial payload delivery.

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` `aaa94d56a54e018796cfe9817ee8905f699a8e46b1be2ec60946b301b568b8cc`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	2454 bytes

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