named configured to answer from stale cache may terminate unexpectedly at recursive-clients soft quota

CVE-2022-3924
7.5HIGH

Key Information

Vendor
Isc
Status
Bind 9
Vendor
CVE Published:
25 January 2023

Badges

👾 Exploit Exists

Summary

This issue can affect BIND 9 resolvers with `stale-answer-enable yes;` that also make use of the option `stale-answer-client-timeout`, configured with a value greater than zero. If the resolver receives many queries that require recursion, there will be a corresponding increase in the number of clients that are waiting for recursion to complete. If there are sufficient clients already waiting when a new client query is received so that it is necessary to SERVFAIL the longest waiting client (see BIND 9 ARM `recursive-clients` limit and soft quota), then it is possible for a race to occur between providing a stale answer to this older client and sending an early timeout SERVFAIL, which may cause an assertion failure. This issue affects BIND 9 versions 9.16.12 through 9.16.36, 9.18.0 through 9.18.10, 9.19.0 through 9.19.8, and 9.16.12-S1 through 9.16.36-S1.

Affected Version(s)

BIND 9 <= 9.16.36

BIND 9 <= 9.18.10

BIND 9 <= 9.19.8

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit exists.

  • Vulnerability published.

  • Vulnerability Reserved.

Collectors

NVD DatabaseMitre Database

Credit

ISC would like to thank Maksym Odinintsev from AWS for bringing this vulnerability to our attention.
.