CVE-2021-25216 Detail

Current Description

In BIND 9.5.0 -> 9.11.29, 9.12.0 -> 9.16.13, and versions BIND 9.11.3-S1 -> 9.11.29-S1 and 9.16.8-S1 -> 9.16.13-S1 of BIND Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.1 of the BIND 9.17 development branch, BIND servers are vulnerable if they are running an affected version and are configured to use GSS-TSIG features. In a configuration which uses BIND's default settings the vulnerable code path is not exposed, but a server can be rendered vulnerable by explicitly setting values for the tkey-gssapi-keytab or tkey-gssapi-credential configuration options. Although the default configuration is not vulnerable, GSS-TSIG is frequently used in networks where BIND is integrated with Samba, as well as in mixed-server environments that combine BIND servers with Active Directory domain controllers. For servers that meet these conditions, the ISC SPNEGO implementation is vulnerable to various attacks, depending on the CPU architecture for which BIND was built: For named binaries compiled for 64-bit platforms, this flaw can be used to trigger a buffer over-read, leading to a server crash. For named binaries compiled for 32-bit platforms, this flaw can be used to trigger a server crash due to a buffer overflow and possibly also to achieve remote code execution. We have determined that standard SPNEGO implementations are available in the MIT and Heimdal Kerberos libraries, which support a broad range of operating systems, rendering the ISC implementation unnecessary and obsolete. Therefore, to reduce the attack surface for BIND users, we will be removing the ISC SPNEGO implementation in the April releases of BIND 9.11 and 9.16 (it had already been dropped from BIND 9.17). We would not normally remove something from a stable ESV (Extended Support Version) of BIND, but since system libraries can replace the ISC SPNEGO implementation, we have made an exception in this case for reasons of stability and security.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  9.8 CRITICAL
Vector:  CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Nist CVSS score does not match with CNA score
CNA:  Internet Systems Consortium (ISC)
Base Score:  8.1 HIGH
Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://www.openwall.com/lists/oss-security/2021/04/29/1 Mailing List  Third Party Advisory 
http://www.openwall.com/lists/oss-security/2021/04/29/2 Mailing List  Third Party Advisory 
http://www.openwall.com/lists/oss-security/2021/04/29/3 Mailing List  Third Party Advisory 
http://www.openwall.com/lists/oss-security/2021/04/29/4 Mailing List  Third Party Advisory 
https://kb.isc.org/v1/docs/cve-2021-25215 Not Applicable 
https://lists.debian.org/debian-lts-announce/2021/05/msg00001.html Mailing List  Third Party Advisory 
https://security.netapp.com/advisory/ntap-20210521-0006/
https://www.debian.org/security/2021/dsa-4909 Third Party Advisory 
https://www.zerodayinitiative.com/advisories/ZDI-21-657/

Weakness Enumeration

CWE-ID CWE Name Source
CWE-617 Reachable Assertion cwe source acceptance level NIST  

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Change History

8 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-25216
NVD Published Date:
04/28/2021
NVD Last Modified:
06/07/2021
Source:
Internet Systems Consortium (ISC)