{{short description|Computer on a network used to access a separate security zone}} {{Redirect|Jump box|boxes used in jumping exercises|Plyometrics|an apparatus for starting a vehicle|Jump start (vehicle)#Other methods}} {{Multiple issues| {{More citations needed|article|date=October 2021}} {{Original research|date=October 2021}} }} A '''jump server''', '''jump host''' or '''jump box''' is a system on a [[Computer network|network]] used to access and manage devices in a separate security zone. A jump server is a [[Hardening (computing)|hardened]] and monitored device that spans two dissimilar security zones and provides a controlled means of access between them. The most common example is managing a host in a [[DMZ (computing)|DMZ]] from trusted networks or computers.
==Background== In the 1990s, when co-location facilities became more common, there was a need to provide access between dissimilar security zones. The jump server concept emerged to meet this need. The jump server would span the two networks and typically be used in conjunction with a [[Proxy server|proxy service]] such as [[SOCKS]] to provide access from an administrative desktop to the managed device. As [[Tunneling protocol#SSH|SSH-based tunneling]] became common, jump servers became the de facto method of access.
==Implementation== Jump servers are often placed between a secure zone and a DMZ to provide transparent management of devices on the DMZ once a management session has been established. The jump server acts as a [[Single Audit|single audit]] point for traffic and also a single place where user accounts can be managed. A prospective administrator must log into the jump server in order to gain access to the DMZ assets, and all access can be logged for later audit.
=== Unix === A typical configuration is a hardened [[Unix]] (or [[Unix-like]]) machine configured with [[SSH]] and a local [[Firewall (computing)|firewall]]. An administrator connects to a target machine in the DMZ by making an SSH connection from the administrator's personal computer to the jump server and then using SSH forwarding to access the target machine.
Using SSH port forwarding or an SSH-based tunnel to the target host allows the use of insecure protocols to manage servers without creating special firewall rules or exposing the traffic on the inside network.
=== Windows === A typical configuration is a [[Windows Server|Windows server]] running [[Remote Desktop Services]] that administrators connect to; this isolates the secure infrastructure from the configuration of the administrator's workstation.<ref>{{Cite web|url=https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/plan/security-best-practices/implementing-secure-administrative-hosts|title=Implementing Secure Administrative Hosts|website=docs.microsoft.com|date=29 July 2021 }}</ref> It is also possible to enable [[OpenSSH]] server on Windows 10 (build 1809 and later) and Windows Server editions 2019 & 2022.<ref>{{Cite web |last=robinharwood |title=Get started with OpenSSH for Windows |url=https://learn.microsoft.com/en-us/windows-server/administration/openssh/openssh_install_firstuse |access-date=2022-12-02 |website=learn.microsoft.com |language=en-us}}</ref>
==Security risks== A jump server is a risk in a network's design.<ref>{{Cite web|url=https://www.csoonline.com/article/2612700/security-jump-boxes-improve-security-if-you-set-them-up-right.html|title='Jump boxes' and SAWs improve security, if you set them up right|first=Roger A.|last=Grimes|date=July 26, 2017|website=CSO Online}}</ref> There are several ways of improving the security of the jump server, including:
* Properly subnetting / segmenting the network,<ref name="Pompon Vinberg 2021">{{cite web |last1=Pompon |first1=Raymond |last2=Vinberg |first2=Sander |title=Protecting Critical Systems with Isolation and Jump Boxes - F5 Labs |website=F5 Labs |date=2021-09-21 |url=https://www.f5.com/labs/articles/cisotociso/protecting-critical-systems-with-isolation-and-jump-boxes |access-date=2022-01-28}}</ref> and securing [[VLANs]] using a [[Firewall (computing)|firewall]]<ref name="Hess"/> or [[Router (computing)|router]]. * Using higher security authentication, such as [[multi-factor authentication]].<ref name="Hess">{{cite web |last=Hess |first=Ken |title=Jump Box Security » Linux Magazine |website=Linux Magazine |url=http://www.linux-magazine.com/Online/Features/Jump-Box-Security |access-date=2022-01-28}}</ref> * Keeping the [[operating system]] and software on the jump server up to date.<ref name="Applied Risk 2021">{{cite web |title=4 OT/IT network segmentation techniques - selecting a cyber resilient configuration- Applied Risk |website=Applied Risk |date=2021-11-24 |url=https://applied-risk.com/resources/4-ot-it-network-segmentation-techniques-selecting-a-cyber-resilient-configuration |access-date=2022-01-28}}</ref> * Using [[Access control list|ACLs]] to restrict access.<ref name="Intelligent Systems Monitoring 2018">{{cite web |title=Jump server |website=Intelligent Systems Monitoring – Systems Monitoring Made Easy |date=2018-05-03 |url=https://intelligentsystemsmonitoring.com/tag/jump-server/ |access-date=2022-01-28}}</ref> * Not allowing outbound access to the rest of the internet from the jump server.<ref name="NERC 2011">{{cite web |title=Guidance for Secure Interactive Remote Access |website=North American Electric Reliability Corporation |date=2011-08-24 |url=https://www.nerc.com/fileUploads/File/Events%20Analysis/FINAL-Guidance_for_Secure_Interactive_Remote_Access.pdf|access-date=2022-01-28 |page=38}}</ref> * Restricting which programs can be run on the jump server.<ref name="Grimes 2017">{{cite web |last=Grimes |first=Roger A. |title='Jump boxes' and SAWs improve security, if you set them up right |website=CSO Online |date=2017-07-26 |url=https://www.csoonline.com/article/2612700/security-jump-boxes-improve-security-if-you-set-them-up-right.html |access-date=2022-01-28}}</ref> * Enabling strong logging for monitoring and alerting of suspicious activity.<ref name="Applied Risk 2021"/> When enhanced security features are required, such as policing client environments, a [[VPN]] may be a suitable replacement.<ref>{{Cite web archived|url=http://radar.oreilly.com/2014/01/is-the-jump-box-obsolete.html|title=Is the Jump Box Obsolete?|first=Rajat|last=Bhargava|date=January 10, 2014|website=O'Reilly Radar|archive-date=2019-04-22}}</ref>
==See also== * [[Bastion host]] * [[Proxy server]]
==References== {{Reflist}}
==External links== *{{cite web |url=http://www.atsec.de/fileadmin/user_upload/whitepaper/ISSE_2009-Secure_network_zones-Peter_Wimmer.pdf |archive-url=https://web.archive.org/web/20160308235020/https://www.atsec.de/fileadmin/user_upload/whitepaper/ISSE_2009-Secure_network_zones-Peter_Wimmer.pdf |archive-date=2016-03-08 |title=Secure Network Zones |website=ATSEC Information Security |url-status=dead |first=Peter Kai |last=Wimmer}} *{{cite web |title=Installation of a Secure User-Chrooted SSH Jumphost |first=Roland |last=Mathis |date=2004-09-20 |url=http://www.giac.org/paper/gcux/266/installation-secure-user-chrooted-ssh-jumphost/106535 |website=GIAC |access-date=2019-06-12 |format=PDF}}
[[Category:Computer network security]] [[Category:Network architecture]]