add a reference to the Kaspersky analysis which covers all 4 CVEs

Author: sfewer-r7

modules/exploits/windows/http/sharepoint_toolpane_rce.rb

@@ -40,6 +40,8 @@ def initialize(info = {})
           ['URL', 'https://blog.viettelcybersecurity.com/sharepoint-toolshell/'],
           # LeakIX blog which captured the malicious request for the in-the-wild exploit.
           ['URL', 'https://blog.leakix.net/2025/07/using-their-own-weapons-for-defense-a-sharepoint-story/'],
+          # Technical analysis of CVE-2025-49704, CVE-2025-49706, CVE-2025-53770 and CVE-2025-53771 by Kaspersky.
+          ['URL', 'https://securelist.com/toolshell-explained/'],
           # ZDI advisories for CVE-2025-49704 and CVE-2025-49706, discovered by Viettel Cyber Security.
           ['URL', 'https://www.zerodayinitiative.com/advisories/ZDI-25-580/'],
           ['URL', 'https://www.zerodayinitiative.com/advisories/ZDI-25-581/'],