A vulnerability was found in Sambas rpcecho development server, a non-Windows RPC server used to test Sambas DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the rpcecho service operates with only one worker in the main RPC task, allowing calls to the rpcecho server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a sleep() call in the dcesrv_echo_TestSleep() function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the rpcecho server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as rpcecho runs in the main RPC task.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Samba | Samba | 4.0.0 (including) | 4.17.12 (excluding) |
| Samba | Samba | 4.18.0 (including) | 4.18.8 (excluding) |
| Samba | Samba | 4.19.0 (including) | 4.19.1 (excluding) |