Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 f100897c4cae03e4…

MALICIOUS

Office (OLE) / .XLSX

52.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 49faae5461abecacb322de16b7845f2e SHA-1: c8bbe2d6039426d6fe95c7d3e3d1cde0d2a49866 SHA-256: f100897c4cae03e45664eb3ad07afa49c1192c639612165d1e927e897685b41e
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

The sample contains Excel 4.0 macros, including an Auto_Open function, which is a known technique for executing malicious code. The macro attempts to download a payload from the URL http://parosdiving.com/catsdeal/color.php using the command 'ndll32 ,DllRegisterServer'. The presence of the 'SE_ENABLE_LURE' heuristic indicates the document likely prompts the user to enable macros, further facilitating the execution of the malicious payload.

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.

FilenameKindSourceSize
xlm_macros.txt
a86dec99e2013db52fcb6c6382b9017e3956457f0a39ff5efd1f9ebf10b6deee
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2321 bytes