#VU48444 Uncontrolled Recursion in Kerberos 5 - CVE-2020-28196
Vulnerability identifier: #VU48444
Vulnerability risk: Medium
CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2020-28196
CWE-ID:
CWE-674
Exploitation vector: Network
Exploit availability: No
Vulnerable software:
Kerberos 5
Client/Desktop applications /
Software for system administration
Vendor: MIT
Description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to uncontrolled recursion in MIT Kerberos 5 (aka krb5) implementation when processing ASN.1-encoded Kerberos messages in lib/krb5/asn.1/asn1_encode.c. A remote attacker can pass specially crafted data to the application that uses Kerberos and perform a denial of service (DoS) attack.
Mitigation
Install update from vendor's website.
Vulnerable software versions
Kerberos 5: 1.17 - 1.18.2
External links
https://github.com/krb5/krb5/commit/57415dda6cf04e73ffc3723be518eddfae599bfd
https://lists.debian.org/debian-lts-announce/2020/11/msg00011.html
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/73IGOG6CZAVMVNS4GGRMOLOZ7B6QVA7F/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KPH2V3WSQTELROZK3GFCPQDOFLKIZ6H5/
https://security.gentoo.org/glsa/202011-17
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
