CVE-2020-8617

Summary

Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.

Affected Software

VendorProductVersion RangeStatus
ISCBIND99.0.0 -> 9.11.18, 9.12.0 -> 9.12.4-P2, 9.14.0 -> 9.14.11, 9.16.0 -> 9.16.2, and releases 9.17.0 -> 9.17.1 of the 9.17 experimental development branch. All releases in the obsolete 9.13 and 9.15 development branches. All releases of BIND Supported Preview Edition from 9.9.3-S1 -> 9.11.18-S1affected

Weaknesses

  • An error in BIND code which checks the validity of messages containing TSIG resource records can be exploited by an attacker to trigger an assertion failure in tsig.c, resulting in denial of service to clients. BIND 9.0.0 -> 9.11.18, 9.12.0 -> 9.12.4-P2, 9.14.0 -> 9.14.11, 9.16.0 -> 9.16.2, and releases 9.17.0 -> 9.17.1 of the 9.17 experimental development branch. All releases in the obsolete 9.13 and 9.15 development branches. All releases of BIND Supported Preview Edition from 9.9.3-S1 -> 9.11.18-S1.

Workarounds

None known.

ADP Enrichment

CVE Program Container

Additional References

References