If a third-party service provider is given remote access to a server so that software can be installed remotely,...
what are the potential risks? Giving any third-party provider access to your company's systems is a security risk. Even if there's no malicious intent, or the access is provided for a legitimate business purpose, it should be strictly controlled, if not prohibited.
Let's start with some potential risks and then provide ideas for workarounds. Besides the threat of introducing malware into your systems, there are other technical and business dangers.
First, granting system access to an outsider lowers your security level to that of the external provider. If they have feeble controls, they become the weakest link in your security chain. If a hacker compromises their system, he or she can use that as a backdoor into your network. In parallel, as their risk increases, so does yours.
Second, there are also business and reputation risks. If their breached system is used to gain malicious access to your system, your company's name will also be in the headlines. Bad press will drive away customers, actual and potential business and can even lead to an unwelcome regulatory review.
Third, allowing external access of this nature circumvents technical controls, such as firewalls. If unfettered access is allowed, why bother with firewalls and access controls? You might as well leave your network wide open for anyone to come in. Further, if the software they want to install contains malware, their remote access is a direct pipeline for malicious code into your network.
Before even considering such access, you'll need to do the following. First, conduct a thorough risk assessment of your partners. Even consider an onsite visit to their facilities, particularly their data centers and any other locations housing IT and network infrastructure. Make sure they meet your security standards in the following areas: physical and network security and access and administrative controls. Make sure partners have written information security policies covering all these controls -- and that there is an IT security department that backs them up.
Next, severely restrict access to your systems. The third party should only have access to a segment of your network that is separated from the internal network by firewalls or an isolated subnet. Access should be restricted to only specific IP addresses from the outside party and be limited to a restricted time period and then closely monitored.
However, the best practice for updating third-party software is the reverse. Your IT team should access their network to retrieve updates rather than allowing them to go fishing in yours.