Vulnerability · Published May 19, 2020 · Assigned by isc
CVE-2020-8617A logic error in code which checks TSIG validity can be used to trigger an assertion failure in tsig.c
High 7.5
In plain English
A high-severity security flaw in BIND9 from ISC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 93.3% (higher than 99.8% of all known vulnerabilities). Ready-made attack tooling exists: Metasploit, public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | bind | 9.14.12-r0 | ALPINE-CVE-2020-8617 |
| Alpine:v3.21 | bind | 9.14.12-r0 | ALPINE-CVE-2020-8617 |
| Alpine:v3.22 | bind | 9.14.12-r0 | ALPINE-CVE-2020-8617 |
| Alpine:v3.23 | bind | 9.14.12-r0 | ALPINE-CVE-2020-8617 |
| Alpine:v3.24 | bind | 9.14.12-r0 | ALPINE-CVE-2020-8617 |
| Debian:12 | bind9 | 1:9.16.3-1 | DEBIAN-CVE-2020-8617 |
| Debian:13 | bind9 | 1:9.16.3-1 | DEBIAN-CVE-2020-8617 |
| Debian:14 | bind9 | 1:9.16.3-1 | DEBIAN-CVE-2020-8617 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| ISC | BIND9 | 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 |
References
- https://kb.isc.org/docs/cve-2020-8617 x_refsource_CONFIRM
- [oss-security] 20200519 Two vulnerabilities disclosed in BIND (CVE-2020-8616 and CVE-2020-8617) mailing-list, x_refsource_MLIST
- DSA-4689 vendor-advisory, x_refsource_DEBIAN
- https://security.netapp.com/advisory/ntap-20200522-0002/ x_refsource_CONFIRM
- http://packetstormsecurity.com/files/157836/BIND-TSIG-Denial-Of-Service.html x_refsource_MISC
- USN-4365-2 vendor-advisory, x_refsource_UBUNTU
- USN-4365-1 vendor-advisory, x_refsource_UBUNTU
- [debian-lts-announce] 20200530 [SECURITY] [DLA 2227-1] bind9 security update mailing-list, x_refsource_MLIST
- FEDORA-2020-2d89cbcfd9 vendor-advisory, x_refsource_FEDORA
- FEDORA-2020-f9dcd4e9d5 vendor-advisory, x_refsource_FEDORA
- openSUSE-SU-2020:1699 vendor-advisory, x_refsource_SUSE
- openSUSE-SU-2020:1701 vendor-advisory, x_refsource_SUSE