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

Static analysis result for SHA-256 7624040557a0cbfc…

MALICIOUS

Office (OLE) / .XLSX

52.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 98d377094c0ff009e1b13bfd2f64f71d SHA-1: 7d36ca003b52dcb26b44f3ed08ba48bcc2b5a888 SHA-256: 7624040557a0cbfcc0009493ae9d47de8b499eb3ff1d291a678bf47cf1190353
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an Excel file containing Excel 4.0 macros, indicated by multiple critical heuristic firings related to XLM Auto_Open and dangerous functions. The document body presents a DocuSign lure to encourage macro execution. The extracted macro code contains a call to REGISTER with a URL, suggesting it downloads and executes a second-stage 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
8509a320b6dbe8e21a7582aae9f5aadecc10d9edb75bf6b48bb45573378d0698
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2322 bytes