Office (OLE) / .XLSX malware analysis — malicious · c71b90af1bdd3ea7

MALICIOUS

Office (OLE) / .XLSX

52.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel

MD5: 4cd145a2953051af1f9aecfd1ae175f2 SHA-1: 6a649a6510c02f47796b3a4d1374f787e537f36a SHA-256: c71b90af1bdd3ea734cdbca8b96ab275e11262d328dc076310e97db5ab9c005a

160 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious Link T1059.001 Command and Scripting Interpreter: PowerShell

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro that uses dangerous functions like RUN. The macro is designed to execute a command that downloads a payload from the URL http://parosdiving.com/catsdeal/color.php. The presence of a macro-enable lure further supports the malicious intent.

Heuristics 4

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.
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_macros.txt` `a86dec99e2013db52fcb6c6382b9017e3956457f0a39ff5efd1f9ebf10b6deee`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	2321 bytes

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