Office (OLE) / .XLS malware analysis — malicious · 857e611f97073ca3

MALICIOUS

Office (OLE) / .XLS

111.0 KB Created: 2021-02-06 22:23:31 Authoring application: Microsoft Excel

MD5: c47f62ed93095c6f96cc466eb83026e3 SHA-1: e9fc15734c2751405bea6e0768d4b63454481036 SHA-256: 857e611f97073ca3903a37ad8a962ee6d554f4dfc5a2c5b36e8d78d64c24d53d

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Service Execution: Service Control T1059.001 PowerShell

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 macro with an Auto_Open entry that uses dangerous functions. The extracted macro script reveals a complex PowerShell command constructed using CHAR functions and string concatenation. This command is designed to download a file from 'https://cutt.ly/ckhxN1E', save it as 'h1.exe' in the user's AppData directory, and then execute it.

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` `144f5701502ff1ccab260bbb314d93f5fe2906b871a2b7fb1ced50d31208cd33`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	1237 bytes

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