Collaboration tools like Slack are designed to make bringing external partners, contractors, and agencies into your workspace frictionless. You enter an email address, assign them to a channel, and they are in.
The problem is that the offboarding process for these guests is rarely as seamless.
The accumulation of risk
When an employee leaves, their departure is tied to a formal HR process. When a contractor finishes a project, there is rarely an automated trigger to revoke their access.
Over years, a company's Slack workspace can accumulate hundreds of external guests. These individuals retain access to historical conversations, shared files, and often, integrations that pipe sensitive alerts or customer data directly into channels.
This accumulation is closely tied to the broader dormant account problem: long-standing guest accounts that nobody reviews are functionally dormant, yet remain fully active.
The compliance nightmare
From a compliance perspective, long-standing guest accounts are a nightmare. Frameworks like SOC 2 and ISO 27001 require organizations to regularly review and justify access. An auditor seeing active guest accounts from a vendor whose contract ended two years ago is an immediate red flag.
Regaining control
Security teams need a way to track the lifecycle of external guests. This involves:
- Identifying all external domains present in collaboration tools.
- Setting acceptable lifespans for guest access.
- Automating reviews when those lifespans are exceeded.
External guest accumulation is one of the core access risks Kastrum is built to surface. Kastrum highlights external accounts that have existed in your workspace beyond normal contractor durations, helping you clean up shadow access and enforce least-privilege principles. Explore the full range of solutions.