Tobias Klein

#644of 53,633
287.7Total CVSS
Vulnerabilities · 42
Medium
22
High
20
PT-2020-5331
7.5
2016-09-28
Isc · Bind · CVE-2020-8617
**Name of the Vulnerable Software and Affected Versions** BIND versions 9.0.0 through 9.11.18 BIND versions 9.12.0 through 9.12.4-P2 BIND versions 9.14.0 through 9.14.11 BIND versions 9.16.0 through 9.16.2 BIND versions 9.17.0 through 9.17.1 BIND all releases in 9.13 and 9.15 development branches BIND versions 9.9.3-S1 through 9.11.18-S1 **Description** The issue is related to a logic error in the code that checks TSIG validity, which can be exploited by an attacker to trigger an assertion failure in tsig.c, resulting in a denial of service. An attacker may potentially cause a BIND server to reach an inconsistent state if they know or successfully guess 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. **Recommendations** For BIND versions 9.0.0 through 9.11.18, update to a version after 9.11.18 to resolve the issue. For BIND versions 9.12.0 through 9.12.4-P2, update to a version after 9.12.4-P2 to resolve the issue. For BIND versions 9.14.0 through 9.14.11, update to a version after 9.14.11 to resolve the issue. For BIND versions 9.16.0 through 9.16.2, update to a version after 9.16.2 to resolve the issue. For BIND versions 9.17.0 through 9.17.1, update to a version after 9.17.1 to resolve the issue. For BIND all releases in 9.13 and 9.15 development branches, update to a version outside of these branches to resolve the issue. For BIND versions 9.9.3-S1 through 9.11.18-S1, update to a version after 9.11.18-S1 to resolve the issue. As a temporary workaround, consider disabling the `tsig.c` function until a patch is available. Restrict access to the TSIG resource records to minimize the risk of exploitation. Avoid using the TSIG key in the affected BIND server until the issue is resolved.