Security practices (archived)
Effective date: 24th May 2018
We take the security of your data very seriously at Slack. As transparency is one of the principles on which our company is built, we aim to be as clear and open as we can about the way that we handle security.
If you have additional questions regarding security, we’d be happy to answer them. Please write to feedback@slack.com and we will respond as quickly as we can.
Confidentiality
We place strict controls over our employees’ access to the data that you and your users make available via the Slack services, as more specifically defined in your agreement with Slack covering the use of the Slack services (‘Customer Data’). The operation of the Slack services requires that some employees have access to the systems which store and process Customer Data. For example, in order to diagnose a problem that you are having with the Slack services, we may need to access your Customer Data. These employees are prohibited from using these permissions to view Customer Data unless it is necessary to do so. We have technical controls and audit policies in place to ensure that any access to Customer Data is logged.
All our employees and contract personnel are bound to our policies regarding Customer Data, and we treat these issues as matters of the highest importance within our company.
Personnel practices
Slack conducts background checks on all employees before employment, and employees receive privacy and security training during onboarding as well as on an ongoing basis. All employees are required to read and sign our comprehensive information security policy covering the security, availability and confidentiality of the Slack services.
Compliance
The following security-related audits and certifications are applicable to the Slack services:
- ISO 27001 and ISO 27018: Slack has achieved ISO 27001 and ISO 27018 compliance. You can download the ISO 27001 certificate here and the ISO 27018 certificate here. A copy of the Statement of Applicability is available upon request from your account manager.
- Service Organisation Control (SOC) reports: Slack has undergone an SOC 2 audit, and a copy of Slack’s most recent report is available upon request from your account manager. Additionally, our SOC 3 report is available for download here.
- PCI: Slack is a PCI Level 4 merchant and has completed the Payment Card Industry Data Security Standard’s SAQ-A. We use a third party to process credit card information securely. Slack is not currently a PCI-certified service provider.
The environment that hosts the Slack services maintains multiple certifications for its data centres, including ISO 27001 compliance, FedRAMP authorisation, PCI certification and SOC reports. For more information about their certification and compliance, please visit the AWS Security website, AWS Compliance website, Google Security website and Google Compliance website.
Security features for team members and administrators
In addition to the work that we do at the infrastructure level, we provide team administrators of paid versions of the Slack services with additional tools to enable their own users to protect their Customer Data.
Access logging
Detailed access logs are available both to users and administrators of paid teams. We log every time an account signs in, noting the type of device used and the IP address of the connection.
Team administrators and owners of paid teams can review consolidated access logs for their whole team. We also make it easy for administrators to remotely terminate all connections and sign out all devices authenticated to the Slack services at any time, on demand.
Team-wide two-factor authentication
Team administrators can require all users to set up two-factor authentication on their accounts. Instructions for doing this are available on our Help Centre.
Single sign-on
Administrators of paid teams can integrate their Slack services instance with a variety of single-sign-on providers. Teams on the ‘Standard’ subscription can enable Google Apps for Domains as their authentication provider, and teams on the ‘Plus’ subscription can enable SAML SSO with providers such as OneLogin, Okta, Centrify and Ping Identity.
Data retention
Owners of paid Slack teams can configure custom message retention policies on a team-wide and per-channel basis. Setting a custom duration for retention means that messages or files older than the duration that you set will be deleted on a nightly basis.
Deletion of Customer Data
Slack provides the option for workspace primary owners to delete Customer Data at any time during a subscription term. Within 24 hours of deletion initiated by a workspace primary owner, Slack hard deletes all information from currently running production systems (excluding team and channel names, and search terms embedded in URLs in web server access logs). Slack services backups are destroyed within 14 days.*
Return of Customer Data
Information about the export capabilities of the Slack services can be found in our Help Centre.
Data encryption in transit and at rest
The Slack services support the latest recommended secure cipher suites and protocols to encrypt all traffic in transit. Customer Data is encrypted at rest.
We monitor the changing cryptographic landscape closely and work promptly to upgrade the service to respond to new cryptographic weaknesses as they are discovered and implement best practices as they evolve. For encryption in transit, we do this while also balancing the need for compatibility for older clients.
Availability
We understand that you rely on the Slack services to work. We’re committed to making Slack a highly available service that you can count on. Our infrastructure runs on systems that are fault tolerant, for failures of individual servers or even entire data centres. Our operations team tests disaster-recovery measures regularly and staffs a round-the-clock on-call team to quickly resolve unexpected incidents.
Disaster recovery
Customer Data is stored redundantly at multiple locations in our hosting provider’s data centres to ensure availability. We have well-tested backup and restoration procedures, which allow recovery from a major disaster. Customer Data and our source code are automatically backed up nightly. The operations team is alerted in case of a failure with this system. Backups are fully tested at least every 90 days to confirm that our processes and tools work as expected.
Network protection
In addition to sophisticated system monitoring and logging, we have implemented two-factor authentication for all server access across our production environment. Firewalls are configured according to industry best practices and unnecessary ports are blocked by configuration with AWS security groups.
Host management
We perform automated vulnerability scans on our production hosts and remediate any findings that present a risk to our environment. We enforce screens lockouts and the usage of full disk encryption for company laptops.
Logging
Slack maintains an extensive, centralised logging environment in its production environment which contains information pertaining to security, monitoring, availability, access and other metrics about the Slack services. These logs are analysed for security events via automated monitoring software, overseen by the security team.
Incident management and response
In the event of a security breach, Slack will promptly notify you of any unauthorised access to your Customer Data. Slack has incident management policies and procedures in place to handle such an event.
External security audits
We contract with respected external security firms who perform regular audits of the Slack services to verify that our security practices are sound and to monitor the Slack services for new vulnerabilities discovered by the security research community. In addition to periodic and targeted audits of the Slack services and features, we also employ the use of continuous hybrid automated scanning of our web platform.
Product security practices
New features, functionality and design changes go through a security review process facilitated by the security team. In addition, our code is audited with automated static analysis software, tested and manually peer reviewed prior to being deployed to production. The security team works closely with development teams to resolve any additional security concerns that may arise during development.
Slack also operates a security bug bounty programme. Security researchers around the world continuously test the security of the Slack services, and report issues via the programme. More details of this programme are available at the bounty site.
*Slack services backups are destroyed within 14 days, except that during an ongoing investigation of an incident, this period may be temporarily extended.