CVE-2023-42669

A vulnerability was found in Samba’s “rpcecho” development server, a
non-Windows RPC server used to test Samba’s 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.

Bugs

• <https://bugzilla.samba.org/show_bug.cgi?id=15474&gt;