While going through a vulnerability scan for PCI compliancy, the report noted that IIS 7 on a Small Business Server 2008 was still using SSL v2.0 instead of SSL 3.0 or TLS 1.0. To disable SSL v2.0:
- Click Start, click Run, type regedt32 or type regedit, and then click OK.
- In Registry Editor, locate the following registry key:HKey_Local_MachineSystemCurrentControlSetControlSecurityProvidersSCHANNELProtocolsSSL 2.0Server
- On the Edit menu, click Add Value.
- In the Data Type list, click DWORD.
- In the Value Name box, type Enabled, and then click OK.Note If this value is present, double-click the value to edit its current value.
- Type 00000000 in Binary Editor to set the value of the new key equal to “0”.
- Click OK. Restart the computer.
IIS negotiates the encryption with the client browser. An attacker could use a tool that tells the server it has only sslv2 (which is weaker) available. If you disable sslv2 it only uses v3 or tls, as requested by browser. A browser only supporting sslv2 would fail.
This applies to Windows Server 2003, and Windows Server 2008, and both versions of SBS.