A truncated TSIG response can lead to an assertion failure
CVE-2020-8622

6.5MEDIUM

Key Information:

Vendor

Isc
Status
Bind9
Vendor
CVE Published:
21 August 2020

Badges

👾 Exploit Exists

What is CVE-2020-8622?

In BIND 9.0.0 -> 9.11.21, 9.12.0 -> 9.16.5, 9.17.0 -> 9.17.3, also affects 9.9.3-S1 -> 9.11.21-S1 of the BIND 9 Supported Preview Edition, An attacker on the network path for a TSIG-signed request, or operating the server receiving the TSIG-signed request, could send a truncated response to that request, triggering an assertion failure, causing the server to exit. Alternately, an off-path attacker would have to correctly guess when a TSIG-signed request was sent, along with other characteristics of the packet and message, and spoof a truncated response to trigger an assertion failure, causing the server to exit.

Affected Version(s)

BIND9 9.0.0

BIND9 < 9.11.22

BIND9 9.12.0

References

https://kb.isc.org/docs/cve-2020-8622
x_refsource_CONFIRM
https://lists.fedoraproject.org/archives/list/package-ann...
vendor-advisoryx_refsource_FEDORA
https://usn.ubuntu.com/4468-1/
vendor-advisoryx_refsource_UBUNTU

EPSS Score

5% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

ISC would like to thank Dave Feldman, Jeff Warren, and Joel Cunningham of Oracle for bringing this vulnerability to our attention.
.