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

Static analysis result for SHA-256 3a5db7906b52a618…

MALICIOUS

Office (OLE) / .XLS

426.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 8a3f53b220a4b31a940b4ad4a007c668 SHA-1: 793640f8c083924f30d6a1825cfa197f57c9e8b9 SHA-256: 3a5db7906b52a618d760a16832c15427e8f8ac6c3443efa09106aeac9d5418d7
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.004 Unix Shell T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

The sample is an Excel file containing both XLM and VBA macros. The presence of Workbook_Open and Auto_Open macros, along with heuristics indicating dangerous functions like RUN, suggests an attempt to automatically execute malicious code upon opening. The document body contains a URL, and the heuristics indicate the use of ShellExecute and URLDownloadToFile APIs, pointing towards the download and execution of a second-stage payload from the provided URL. The 'Macro/content-enable lure' heuristic further supports the attack pattern of tricking the user into enabling macros.

Heuristics 8

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • XLM Auto_Open with dangerous formula APIs high 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • 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
  • 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 https://mueblesmaple.com.mx/19.gif�
    • https://mueblesmaple.com.mx/19.gif
    • http://ns.adobe.com/xap/1.0/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
e26e570691e37538cb153a294d4bd7899ebc79f39ec63fd34cf1eae37efa26f6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9455 bytes
macros.bas
8c21c322bb8b23e7dbfa4da0de1c41676162b0810e96582d1365413c12adc768
vba-macro oletools.olevba.extract_macros (decoded VBA source) 977 bytes