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

Static analysis result for SHA-256 b3c5856cb1a05f2d…

MALICIOUS

Office (OLE) / .XLSX

52.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 3bacae0b7a3a734fe9b20f9bbe0158e8 SHA-1: 079d6498acdf9d82d1b37274afd45c0d8deec262 SHA-256: b3c5856cb1a05f2dfc3480b3076aa7a6e4d295e89a174349975db28da027d78d
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious File

The sample contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macro uses dangerous functions like RUN, indicating an attempt to execute arbitrary code. The document body and extracted script fragments suggest a lure to enable macros, a common technique for malware delivery. The script attempts to construct a URL for downloading a payload, indicated by the presence of 'http://soberlifeco.com/contra/storage.php' and the function 'REGISTER' which is often used in conjunction with downloading and executing code. The presence of 'ndll32.dllRegisterServer' further suggests dynamic-link library registration, likely for malicious purposes.

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
8509a320b6dbe8e21a7582aae9f5aadecc10d9edb75bf6b48bb45573378d0698		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2322 bytes

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