#VU26625 Buffer overflow in telnet - CVE-2020-10188
Vulnerability identifier: #VU26625
Vulnerability risk: High
CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]
CVE-ID: CVE-2020-10188
CWE-ID:
CWE-119
Exploitation vector: Network
Exploit availability: No
Vulnerable software:
telnet
Server applications /
Remote management servers, RDP, SSH
Vendor: netkit.org
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
https://appgateresearch.blogspot.com/2020/02/bravestarr-fedora-31-netkit-telnetd_28.html
https://github.com/krb5/krb5-appl/blob/d00cd671dfe945791b33d4f1f6a5c57ae1667ef8/telnet/telnetd/utility.c#L205-L216
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7FMTRRQTYKWZD2GMXX3GLZV46OLPCLVK/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HLU6FL24BSQQEB2SJC26NLJ2MANQDA7M/
https://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.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
