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

Static analysis result for SHA-256 684500f375d70aa2…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 057dab314009c3e022a4436424d5b56e SHA-1: ea696d06a690d8b8dc992117b760aed4ff1feabd SHA-256: 684500f375d70aa2c092a9a0404076ca69e6fc50a3ffddfc921de809c1238c1e
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macros utilize dangerous functions like RUN and CALL, and attempt to construct a URL by concatenating strings. The primary purpose appears to be downloading a second-stage payload from the embedded URL http://l.loungu.com/ds/231120.gif, as indicated by the ClamAV detection and the presence of embedded URLs.

Heuristics 6

  • 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.
  • ClamAV: Doc.Downloader.Docusign0521-9864805-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Docusign0521-9864805-0
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://l.loungu.com/ds/231120.gif
    • http://l.loungu.com/ds/231120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
abb07963271b08693dfd8d409076720f3110aa546c958d7d37a9d0626b110da2
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6297 bytes