CVE-2023-42669

Summary

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.

Affected Software

VendorProductVersion RangeStatus
4.0.0 < 4.17.12affected
4.18.0 < 4.18.8affected
4.19.0affected
Red HatRed Hat Enterprise Linux 80:4.18.6-2.el8_9 < *unaffected
Red HatRed Hat Enterprise Linux 80:4.18.6-2.el8_9 < *unaffected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support0:4.15.5-13.el8_6 < *unaffected
Red HatRed Hat Enterprise Linux 8.8 Extended Update Support0:4.17.5-4.el8_8 < *unaffected
Red HatRed Hat Enterprise Linux 90:4.18.6-101.el9_3 < *unaffected
Red HatRed Hat Enterprise Linux 90:4.18.6-101.el9_3 < *unaffected
Red HatRed Hat Enterprise Linux 9.0 Extended Update Support0:4.15.5-111.el9_0 < *unaffected
Red HatRed Hat Enterprise Linux 9.2 Extended Update Support0:4.17.5-104.el9_2 < *unaffected
Red HatRed Hat Virtualization 4 for Red Hat Enterprise Linux 80:4.15.5-13.el8_6 < *unaffected

Weaknesses

  • CWE-400: Uncontrolled Resource Consumption

Workarounds

To mitigate this vulnerability, disable rpcecho service on the AD DC by setting:

dcerpc endpoint servers = -rpcecho

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References