Denial of service in MIT Kerberos 5

1) NULL pointer dereference

EUVDB-ID: #VU56828

Risk: Medium

CVSSv3.1: 6 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:U/RC:C]

CVE-ID: CVE-2021-37750

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in the Key Distribution Center (KDC) in kdc/do_tgs_req.c. A remote user can pass specially crafted data via the FAST inner body that lacks a server field, trigger a NULL pointer dereference error and perform a denial of service (DoS) attack.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Kerberos 5: 1.18 - 1.19.2

External links

http://github.com/krb5/krb5/commit/d775c95af7606a51bf79547a94fa52ddd1cb7f49
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MFCLW7D46E4VCREKKH453T5DA4XOLHU2/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.