Denial of service in GNU Inetutils telnetd

1) NULL pointer dereference

EUVDB-ID: #VU67777

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-39028

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

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

The vulnerability exists due to a NULL pointer dereference error in telnetd daemon. A remote attacker can trigger NULL pointer dereference via 0xff 0xf7 or 0xff 0xf8 and crash telnetd.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Inetutils - GNU network utilities: 1.4.0 - 2.3

External links

http://lists.gnu.org/archive/html/bug-inetutils/2022-08/msg00002.html
http://git.hadrons.org/cgit/debian/pkgs/inetutils.git/commit/?id=113da8021710d871c7dd72d2a4d5615d42d64289
http://pierrekim.github.io/blog/2022-08-24-2-byte-dos-freebsd-netbsd-telnetd-netkit-telnetd-inetutils-telnetd-kerberos-telnetd.html

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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