title: Samba: "rpcecho" development server allows denial of service via sleep() call on ad dc
description: 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.
problem types: Uncontrolled Resource Consumption
affected:
{
product: samba
vendor: n/a
versions:
version: 4.19.1, status: unaffected
version: 4.18.8, status: unaffected
version: 4.17.12, status: unaffected
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.18.6-2.el8_9, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:enterprise_linux:8::appstream, cpe:/a:redhat:enterprise_linux:8::crb, cpe:/o:redhat:enterprise_linux:8::baseos]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.18.6-2.el8_9, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:enterprise_linux:8::appstream, cpe:/a:redhat:enterprise_linux:8::crb, cpe:/o:redhat:enterprise_linux:8::baseos]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8.6 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.15.5-13.el8_6, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:8.6::crb, cpe:/a:redhat:rhel_eus:8.6::appstream, cpe:/o:redhat:rhel_eus:8.6::baseos, cpe:/o:redhat:enterprise_linux:8::hypervisor]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8.8 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.17.5-4.el8_8, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/o:redhat:rhel_eus:8.8::baseos, cpe:/a:redhat:rhel_eus:8.8::appstream, cpe:/a:redhat:rhel_eus:8.8::crb]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.18.6-101.el9_3, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:enterprise_linux:9::resilientstorage, cpe:/a:redhat:enterprise_linux:9::appstream, cpe:/o:redhat:enterprise_linux:9::baseos, cpe:/a:redhat:enterprise_linux:9::crb]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.18.6-101.el9_3, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:enterprise_linux:9::resilientstorage, cpe:/a:redhat:enterprise_linux:9::appstream, cpe:/o:redhat:enterprise_linux:9::baseos, cpe:/a:redhat:enterprise_linux:9::crb]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.0 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.15.5-111.el9_0, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:9.0::crb, cpe:/a:redhat:rhel_eus:9.0::appstream, cpe:/o:redhat:rhel_eus:9.0::baseos, cpe:/a:redhat:rhel_eus:9.0::resilientstorage]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.2 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.17.5-104.el9_2, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:9.2::resilientstorage, cpe:/o:redhat:rhel_eus:9.2::baseos, cpe:/a:redhat:rhel_eus:9.2::crb, cpe:/a:redhat:rhel_eus:9.2::appstream]
}
{
vendor: Red Hat
product: Red Hat Virtualization 4 for Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
versions:
version: 0:4.15.5-13.el8_6, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:8.6::crb, cpe:/a:redhat:rhel_eus:8.6::appstream, cpe:/o:redhat:rhel_eus:8.6::baseos, cpe:/o:redhat:enterprise_linux:8::hypervisor]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 6
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: unknown
cpes: cpe:/o:redhat:enterprise_linux:6
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 6
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba4
defaultStatus: unknown
cpes: cpe:/o:redhat:enterprise_linux:6
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 7
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: unknown
cpes: cpe:/o:redhat:enterprise_linux:7
}
{
vendor: Red Hat
product: Red Hat Storage 3
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: samba
defaultStatus: affected
cpes: cpe:/a:redhat:storage:3
}
{
product: Fedora
vendor: Fedora
collectionURL: https://packages.fedoraproject.org/
packageName: samba
defaultStatus: affected
}
metrics:
other: [
content: {'value': 'Moderate', 'namespace': 'https://access.redhat.com/security/updates/classification/'}
type: Red Hat severity rating
]
workarounds: To mitigate this vulnerability, disable rpcecho service on the AD DC by setting:
~~~
dcerpc endpoint servers = -rpcecho
~~~
