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

Static analysis result for SHA-256 bb86b8d034ba6e5a…

MALICIOUS

Office (OLE) / .XLS

54.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 632e0ca8ac2427b22123d2647d9396d9 SHA-1: d07696501ab622c8c251e37d7c6e5311e63e9e47 SHA-256: bb86b8d034ba6e5a3ede0a2c1056ddb735fe6a8cadc930e848d2f8072cfc38e4
300 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1105 Ingress Tool Transfer

The sample contains Excel 4.0 macros with an Auto_Open entry and VBA code that utilizes the URLDownloadToFile API. The VBA script reconstructs the URL 'http://' & Sheets("Files").Range("B60") and attempts to download a file to the path specified in Sheets("Files").Range("B56"). This indicates a downloader functionality, aiming to fetch and execute a second-stage payload from the listed URLs. The presence of an enable-lure further supports the malicious intent.

Heuristics 7

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • 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.
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in 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.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
2a1c7329c4c8792c67abecd81ffa3d95e2243efca26ae8a7b4838634109595bd
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 5046 bytes
macros.bas
aa55a18a3f33259e345c5e53649ac5f2f1d89d5667b734f6c8f841105e5741f2
vba-macro oletools.olevba.extract_macros (decoded VBA source) 1692 bytes