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.
The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
| 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) |
| Samba | Ubuntu | bionic | * |
| Samba | Ubuntu | devel | * |
| Samba | Ubuntu | focal | * |
| Samba | Ubuntu | jammy | * |
| Samba | Ubuntu | lunar | * |
| Samba | Ubuntu | mantic | * |
| Samba | Ubuntu | noble | * |
| Samba | Ubuntu | oracular | * |
| Samba | Ubuntu | trusty | * |
| Samba | Ubuntu | trusty/esm | * |
| Samba | Ubuntu | xenial | * |
| Red Hat Enterprise Linux 8 | RedHat | samba-0:4.18.6-2.el8_9 | * |
| Red Hat Enterprise Linux 8 | RedHat | samba-0:4.18.6-2.el8_9 | * |
| Red Hat Enterprise Linux 8.6 Extended Update Support | RedHat | samba-0:4.15.5-13.el8_6 | * |
| Red Hat Enterprise Linux 8.8 Extended Update Support | RedHat | samba-0:4.17.5-4.el8_8 | * |
| Red Hat Enterprise Linux 9 | RedHat | samba-0:4.18.6-101.el9_3 | * |
| Red Hat Enterprise Linux 9 | RedHat | samba-0:4.18.6-101.el9_3 | * |
| Red Hat Enterprise Linux 9.0 Extended Update Support | RedHat | samba-0:4.15.5-111.el9_0 | * |
| Red Hat Enterprise Linux 9.2 Extended Update Support | RedHat | samba-0:4.17.5-104.el9_2 | * |
| Red Hat Virtualization 4 for Red Hat Enterprise Linux 8 | RedHat | samba-0:4.15.5-13.el8_6 | * |
Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system. There are at least three distinct scenarios which can commonly lead to resource exhaustion:
Resource exhaustion problems are often result due to an incorrect implementation of the following situations:
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.