Remote code execution in netkit telnet

1) Buffer overflow

EUVDB-ID: #VU26625

Risk: High

CVSSv3.1: 9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:U/RC:C]

CVE-ID: CVE-2020-10188

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary involving the netclear and nextitem functions within the utility.c in telnetd daemon from netkit telnet. A remote attacker can end specially crafted data to the telnetd daemon, trigger a boundary error and execute arbitrary code on the target system.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

telnet: 0.17

External links

http://appgateresearch.blogspot.com/2020/02/bravestarr-fedora-31-netkit-telnetd_28.html
http://github.com/krb5/krb5-appl/blob/d00cd671dfe945791b33d4f1f6a5c57ae1667ef8/telnet/telnetd/utility.c#L205-L216
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7FMTRRQTYKWZD2GMXX3GLZV46OLPCLVK/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HLU6FL24BSQQEB2SJC26NLJ2MANQDA7M/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/K3VJ6V2Z3JRNJOBVHSOPMAC76PSSKG6A/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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