Is Slack Secure for Business and Personal Use: 2025 Risks

Slack has changed the way businesses and individuals communicate, making it a go-to tool for workplace collaboration and passion projects. However, with so much sensitive information shared daily, one big question remains.

Is Slack secure for business? The platform uses strong security measures to protect your data while it's being sent and stored — an important factor considering the platform had 42 million active users in 2024¹. But is it enough?

In this guide, I’ll break down Slack’s security features, potential risks, and tips for using it safely. Whether you're a freelancer, business owner, or just someone who wants a secure space to chat, you'll find everything you need to make an informed decision.

Editor's Note: Transparency is one of our core values at vpnMentor, so you should know we are in the same ownership group as ExpressVPN. However, this does not affect our review process.

Is Slack Secure?

Slack is a trusted collaboration tool designed with strong security measures to protect user data. From its encryption to its compliance with industry standards, Slack provides a safe environment for teamwork and communication. It’s a necessity since 77% of the Fortune 100 companies use Slack².

Let’s break down its key security features:

1. Data Encryption

Did you know that more than 1.5 billion messages are sent daily on Slack²? Slack encrypts messages, files, and other content both in transit and at rest. These protections are automatically applied, meaning you don’t need to set them up manually:

• In transit: TLS 1.2 protects communications from interception.
• At rest: Slack uses FIPS 140-2 compliant encryption to safeguard stored data.

2. Regular Security Audits

Slack conducts frequent third-party security audits to proactively identify and fix vulnerabilities. These audits include:

• Independent penetration testing. Ethical hackers simulate cyberattacks to uncover weaknesses in Slack’s infrastructure. These controlled tests help detect vulnerabilities before real attackers can exploit them.
• Internal security reviews. Slack’s dedicated security team continuously analyzes its codebase and infrastructure for vulnerabilities. Before deploying updates, rigorous testing ensures that new features don’t introduce security risks.
• Third-party risk assessments. Slack collaborates with external cybersecurity firms to evaluate its security posture, assess risks, and strengthen defenses against evolving cyber threats.

3. Two-Factor Authentication (2FA)

Enabling 2FA adds an extra layer of security by requiring a second verification step, such as a code sent to your phone. To turn it on:

Go to Profile > Account Settings > Two-Factor Authentication
Follow the prompts to link a mobile device or authentication app

This step helps prevent unauthorized access, even if someone gets hold of your password.

Regularly update your recovery options to avoid lockouts

4. Compliance with Safety Standards

Slack meets key security certifications, including:

• SOC 2 & SOC 3 (protects financial and operational data)
• ISO/IEC 27001 (global security standard)
• GDPR compliance (protects user data in the EU)

These certifications prove that Slack follows strict data protection regulations, similar to those used by Microsoft Azure, Google Cloud, and Amazon Web Services.

5. Granular Access Controls

Admins can customize access permissions to restrict who can view channels, files, or settings. This prevents unauthorized users from accessing private information:

• Go to Settings > Permissions
• Assign roles and limit access to sensitive data based on user roles

6. Scam and Phishing Protection

Slack employs multiple layers of protection to detect and block phishing attempts, malware, and scams before they reach users. Key security measures include:

• Automated threat detection. Slack uses machine learning and heuristic analysis to identify suspicious links, attachments, and messages that could contain phishing attempts or malware.
• Link scanning and malware protection. When users share links in Slack, the platform automatically scans them to check for known malicious URLs. This helps prevent phishing attacks that attempt to steal credentials.
• Domain and account protection. Slack detects suspicious login attempts from unrecognized locations or devices. If unusual activity is detected, Slack may flag or temporarily lock accounts to prevent unauthorized access.

7. Enterprise Key Management (EKM)

Slack’s Enterprise Key Management (EKM) is an advanced security feature designed for organizations that need greater control over their encryption keys. This feature is only available on Slack’s Enterprise Grid plan and requires setup with Slack Support and Amazon Web Services (AWS) Key Management Service (KMS).

With EKM, businesses can:

• Use their own encryption keys. Instead of relying on Slack’s default encryption, organizations can integrate customer-managed encryption keys stored in AWS KMS.
• Control data access. Admins can revoke access to messages and files by rotating encryption keys, limiting exposure in case of a security breach.
• Granular encryption management. Companies can selectively encrypt specific channels or files, ensuring sensitive data is protected while keeping other content easily accessible.
• Monitor security logs. EKM integrates with audit logging tools to provide visibility into who accessed what data and when, allowing businesses to track security events in real time.
• Minimize compliance risks. EKM helps organizations meet strict regulatory and compliance requirements, such as HIPAA, FINRA, and GDPR, by ensuring sensitive data remains under their control.

Safety and Privacy Risks of Using Slack

Slack provides strong security features, but no platform is completely risk-free. Being aware of potential vulnerabilities helps you take proactive steps to protect your data and workspace. Here are the key risks to consider:

1. Data Retention and Privacy

Slack collects and stores various types of user data, including email addresses, usernames, profile details, IP addresses, and device information. It also logs user activity and gathers metadata from features like Slack Huddles (audio/video calls).

While this data is used for functionality and security, it poses a risk if exposed in a data breach. Businesses handling highly sensitive information should consider additional security measures, such as Enterprise Key Management, for greater control.

2. No End-to-End Encryption (E2EE)

Slack encrypts data in transit and at rest, but it doesn’t offer end-to-end encryption (E2EE). This means Slack has access to messages and files for compliance, troubleshooting, and legal purposes.

Unlike E2EE platforms, such as Signal or WhatsApp, where only the sender and receiver can read messages, Slack’s approach leaves some exposure to potential unauthorized access or security incidents. Businesses handling confidential data should carefully evaluate whether this limitation aligns with their security needs.

3. Phishing and Social Engineering Attacks

While Slack has built-in phishing protections, such as link scanning and suspicious activity alerts, phishing attacks remain a significant threat. Cybercriminals often impersonate colleagues, IT staff, or even Slackbot to trick you into sharing sensitive information or clicking malicious links. Additionally, on unsecured WiFi networks, attackers can use man-in-the-middle (MITM) attacks to intercept messages.

4. Open Communities and External Access Risks

Slack's public communities are great for networking but can pose security risks if not managed properly. These groups often include both internal and external users, making it harder to control who has access to shared files and conversations.

In large workspaces, lack of oversight can lead to:

• Accidental data leaks when sensitive information is shared in public channels
• Exposure to unverified users who may have malicious intent
• Difficulty monitoring access, especially when new members join

5. Third-Party Integrations and App Permissions

Slack integrates with thousands of third-party apps (e.g., Google Drive, Zoom, Trello) to improve productivity. However, these integrations often request access to messages, files, and user data, creating potential vulnerabilities if an app is poorly secured or outdated. This can act as a gateway for cyberattacks, exposing critical company resources.

6. System Vulnerabilities

As a widely-used platform, Slack is a high-value target for cyberattacks. Although Slack actively fixes vulnerabilities, the risk window before updates are applied can be critical. Vulnerabilities can arise from:

• Software bugs that hackers exploit before Slack releases a patch
• Misconfigurations in security settings
• Malicious scripts or unauthorized API access

7. Onboarding and Offboarding Risks

Poorly managed onboarding and offboarding can create security risks in Slack. If former employees or contractors aren't removed promptly, they may still have access to sensitive company data. On the flip side, giving new users too many permissions during onboarding can expose information they don’t actually need.

Besides, Admin and Owner roles come with a lot of control, including the ability to change user settings and grant high-level access. If these roles aren’t carefully managed, it can lead to accidental data leaks or intentional misuse.

8. Free Slack Plans

Slack’s free plans lack essential security features, such as EKM for encryption key control, granular admin controls to fine-tune access, and compliance tools required for industry regulations. For businesses handling sensitive data, upgrading to a paid plan may be necessary to gain better security, compliance, and admin oversight.

Slack Security Breaches

Even with strong security measures, Slack isn't immune to breaches. Over the years, several incidents have exposed sensitive company data, highlighting the need for extra precautions. Here are 3 significant breaches:

• Slack GitHub repository breach (December 2022). Unauthorized access to Slack's GitHub repositories raised concerns about developer tools and access controls³. While customer data wasn’t affected, Slack tightened security and reinforced internal protocols.
• Disney Slack leak (July 2024). The hacktivist group NullBulge leaked 1.1 terabytes of internal Disney Slack messages, revealing strategic plans, private conversations, and operational details⁴.
• Nvidia Slack scandal (August 2024). A major leak exposed internal Slack chats, emails, and documents⁴, sparking ethical concerns about how Nvidia handled sensitive data.

Additionally, a cybersecurity firm, KELA, revealed over 17,000 Slack credentials from more than 12,000 workspaces were available for sale on dark web markets⁵, including the now-defunct Genesis Market. This widespread availability of Slack credentials highlights the platform's vulnerability as an attack vector and has been linked to high-profile breaches at companies like Twitter, Electronic Arts, and Disney.

How to Use Slack Safely

Slack workspaces often contain sensitive data such as Twitter or Facebook credentials, credit card details, API keys, and passwords for business tools. Like any online platform, Slack requires smart security practices to keep your data safe. Here’s how you can protect your workspace and minimize risks:

• Use a VPN on public WiFi. Public networks are easy targets for hackers. A VPN encrypts your internet traffic, preventing cybercriminals from intercepting Slack messages. If you frequently work from cafés, airports, or hotels, turn on a trusted VPN to keep your connection secure.
• Create strong passwords (and never share them). A weak password is like leaving your front door unlocked. Use a unique, complex password for Slack, ideally stored in a password manager. Avoid sharing it — even with colleagues — and update it regularly for extra protection.
• Enable invite-only compliance. Restrict workspace access to invited users only. By setting strict invitation protocols, you can prevent unauthorized individuals from joining your workspace. Admins should regularly review members and remove inactive or unnecessary accounts to maintain a safe environment.
• Limit third-party integrations. While third-party apps enhance Slack’s functionality, only integrate tools from trusted sources. Unnecessary or poorly protected integrations can create vulnerabilities. Conduct regular reviews of app permissions and remove any that are outdated or no longer in use.
• Keep Slack updated. New updates often include critical security fixes. Enable automatic updates on all your devices to ensure you’re always running the latest, most secure version of Slack.
• Avoid public Slack communities. Public Slack groups may seem useful, but they can expose you to scams, phishing, and data leaks. If you must use them, avoid sharing sensitive information and be cautious when engaging with strangers.
• Train employees on Slack security. Even the best security features won’t help if employees don’t know how to spot threats. Conduct regular training on phishing scams, permission settings, and reporting suspicious activity to create a security-first mindset in your team.

Slack Alternatives

While Slack remains a popular choice for collaboration, several other platforms like Google Chat and Discord offer unique features, security measures, and pricing models that cater to different needs. Whether you're looking for enhanced encryption, better integration options, or cost-effective solutions, these alternatives can provide valuable options. Here's a comparison of Slack and some of its top alternatives:

FAQs on Slack Security

Can Slack employees access my data?

Yes, Slack employees may access user data for purposes such as troubleshooting and compliance. This includes data like email addresses, usernames, and metadata. While this access is restricted to specific situations, the platform's extensive data retention practices can represent risks if exposed during a breach.

How can I make my Slack workspace more secure?

To enhance your Slack workspace safety, establish clear access controls by assigning roles and permissions that limit user access to sensitive information. Regularly audit your integrations and remove outdated or unverified third-party apps to reduce vulnerabilities. Encourage employees to follow best practices, such as using strong passwords and reporting suspicious activity promptly.

Is Slack HIPAA compliant?

Yes, Slack can be HIPAA compliant, but only under specific conditions. Organizations must use the Enterprise Grid plan and sign a Business Associate Agreement (BAA) with Slack to ensure compliance with HIPAA regulations. However, even with these measures, not all Slack features meet HIPAA requirements.

While direct messages and channels can be configured for compliance, file uploads and certain third-party integrations may not be covered. Businesses handling protected health information (PHI) should carefully manage settings and limit where PHI is shared to maintain compliance.

What should I do if I suspect a phishing attack on Slack?

If you suspect a phishing attack on Slack, avoid clicking on any suspicious links or providing personal information. Immediately report the message to your workspace administrator and Slack support so they can investigate and address the issue. To protect your account, verify that your workspace has robust security measures in place.

Are free Slack plans less secure than paid plans?

Yes, free Slack plans do not include advanced security features, such as Enterprise Key Management (EKM). While suitable for casual users, free plans may expose businesses handling sensitive data to more significant safety risks due to limited control over access and monitoring.

How does Slack handle security breaches?

Slack handles security breaches by promptly investigating incidents, patching vulnerabilities, and implementing stronger safety protocols to prevent recurrence. The platform maintains transparency by notifying affected users and disclosing relevant information about the breach when necessary. In the past, Slack has experienced three notable breaches, highlighting the importance of proactive measures to safeguard user data.

Wrapping Up: Is Slack Secure to Use?

Slack is a secure and reliable platform for team communication, offering encryption, access controls, and compliance options. However, it’s not immune to risks. To keep your workspace safe, it’s important to use strong passwords, enable two-factor authentication, and be mindful of third-party app integrations.

While Slack is generally safe for everyday use, businesses handling sensitive information should take extra precautions. Higher-tier plans offer additional security features, but proper setup and employee awareness play a key role in protecting data. By following best practices and using extra security tools when needed, you can make Slack a safer space for collaboration.

References

1. https://www.businessofapps.com/data/slack-statistics/
2. https://www.demandsage.com/slack-statistics/
3. https://slack.com/intl/en-gb/blog/news/slack-security-update
4. https://www.salesforceben.com/unpacking-the-recent-slack-data-security-breach/?utm_source=chatgpt.com
5. https://www.kelacyber.com/blog/slacking-off-slack-and-the-corporate-attack-surface-landscape/?_gl=1*1u7ox7i*_gcl_au*MjAzNjY0NzUxNi4xNzM4MTU0NTU5