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CVE-2021-25216— A second vulnerability in BIND's GSSAPI security policy negotiation can be targeted by a buffer overflow attack

Quick assessment

Affected
ISC BIND9
Exploitation
High exploitation probability; assess promptly
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

ISC BIND是美国ISC公司的一套实现了DNS协议的开源软件。 BIND 存在缓冲区错误漏洞，该漏洞源于BIND的GSSAPI安全策略。

CVSS 8.1 · High EPSS 82.37% · P100

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2021-25216

Vulnerability Information
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Vulnerability Title
A second vulnerability in BIND's GSSAPI security policy negotiation can be targeted by a buffer overflow attack
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
ISC BIND 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
ISC BIND是美国ISC公司的一套实现了DNS协议的开源软件。 BIND 存在缓冲区错误漏洞，该漏洞源于BIND的GSSAPI安全策略。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
ISC BIND9 Open Source Branches 9.5 though 9.11 9.5.0 through versions before 9.11.31 -

II. Public POCs for CVE-2021-25216

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III. Intelligence Information for CVE-2021-25216

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Vendor Advisories for CVE-2021-25216 (4)

Mailing List Discussions for CVE-2021-25216 (4)

Other References for CVE-2021-25216 (1)

Same Patch Batch · ISC · 2021-04-29 · 3 CVEs total

CVE-2021-25215 7.5 HIGH An assertion check can fail while answering queries for DNAME records that require the DNA
CVE-2021-25214 6.5 MEDIUM A broken inbound incremental zone update (IXFR) can cause named to terminate unexpectedly

IV. Related Vulnerabilities

Same product: BIND9
Same vendor: ISC

V. Comments for CVE-2021-25216

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