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  • Slack’s popularity makes it a top target for cyber threats.
  • Slack vulnerabilities come in two major forms: risks on the user’s part and risks stemming from platform vulnerabilities.
  • Implementing strong authentication and data protection policies can help organizations safeguard against Slack-related security threats.

In the last ten years, Slack has soared in popularity as a critical workplace tool. Praised as the cornerstone of employee efficiency, it’s hailed for its speed, ease of use, and instant communication capabilities, enabling teams to bypass the formality and delays often associated with email.

However, alongside its productivity and collaboration benefits, organizations must acknowledge that Slack poses significant security risks. 

Like all software, this platform is susceptible to bugs and vulnerabilities, and its widespread adoption in corporate settings makes it an attractive target for hackers seeking to exploit these weaknesses.

Moreover, Slack operates within the shared responsibility model of cloud computing. While the platform itself may be secure, a single misconfiguration on the user’s end could jeopardize sensitive data.

Here, we’ll look at Slack’s vulnerabilities, and how to remediate them, in more detail. 

Timeline: Common Slack vulnerabilities

Slack’s widespread adoption as a communication platform has made it a lucrative target for cyber threats.

Inherently, the platform is rich in a wealth of sensitive data, ranging from trade secrets to customer information. For cybercriminals, breaking into Slack is a gold mine, which is why they’ve tried to breach the platforms tens of times in the past few years. 

Here’s a look at some of the most recent breach attempts and the vulnerabilities they relate to:

  • Uber breach (2022): A hacker exploited a vulnerability to gain access to internal systems, including Slack.
  • Rockstar Games breach (2022): Through social engineering tactics, a hacker compromised an employee’s Slack account, absconding with unreleased game footage and proprietary source code.
  • Slack misconfiguration (2022): A flaw in Slack’s infrastructure exposed users’ credentials.
  • EA breach (2021): Cybercriminals leveraged stolen cookies to access an EA employee’s Slack account, resulting in significant data theft.
  • Twitter breach (2020): Attackers breached Twitter’s servers using stolen login credentials to access internal Slack channels.
  • Slack vulnerability (2020): A discovered flaw facilitated automated account takeovers (ATOs).

The very attributes that make Slack so effective for collaboration and connectivity also render it vulnerable to exploitation. Its ease of use and seamless communication make it an attractive target for cyber attackers seeking sensitive data.

Within Slack, the exchange of data, files, messages, and links occurs seamlessly among users, potentially leaving valuable information exposed. While Slack’s features have undoubtedly facilitated the transition to remote work for many companies, they also introduce cybersecurity vulnerabilities.

Therefore, it’s imperative for businesses to implement additional data security measures when leveraging collaborative platforms to safeguard their sensitive information.

Furthermore, these incidents highlight a dual threat within Slack. On one front, there are vulnerabilities inherent to the application itself. On the other, there’s the risk of human error, including falling victim to phishing attacks, misconfigurations, and inadequate privilege management.

The key security risks of using Slack

So far, we’ve explored the risks in Slack on the application side. Now, we’ll explore another key threat: issues arising from misconfigurations and human error. 

The insider threat 

The insider threat presents itself in various forms, whether it’s a disgruntled employee, an unwitting one, or even a cybercriminal with legitimate credentials. Within the realm of Slack, distinguishing between legitimate users and potential threats can be challenging, making it difficult to monitor data access.

Panda Security reported a concerning 47% increase in insider incidents over the past two years. With more employees working remotely, away from the oversight of IT departments, many have grown lax about corporate security protocols. 

This laxity may lead to the inadvertent sharing of confidential data or the practice of sharing passwords among teams for convenience, heightening the risk of data breaches and subsequent compliance fines.

Moreover, verifying user identities within Slack presents its challenges. A recent example is the EA breach, where hackers obtained an EA employee’s Slack credentials. By posing as the employee in need of multi-factor authentication assistance via Slack, they gained access to EA’s corporate network.

Data sprawl

Slack’s seamless sharing capabilities can swiftly transform into a data security nightmare without the implementation of appropriate governance policies. Imagine an employee uploading a sensitive file to Slack, only to later download it onto their personal device via the mobile app – potentially violating legal regulations in the process.

In the absence of a robust data governance strategy, collaboration tools like Slack can easily become a breeding ground for sprawling, unstructured, and sensitive data. Without clear visibility into the whereabouts of sensitive data, who has access to it, and where it’s been transferred, organizations risk experiencing both data breaches and compliance failures.

In essence, without a comprehensive compliance framework to manage data sprawl, Slack can inadvertently become a significant source of data leakage within an organization.

Third-party applications

Slack places the responsibility of adjusting third-party app permissions on the user, leaving room for simple errors or malicious interceptions that could lead to sensitive information falling into unintended hands. In some instances, linked third-party applications may gain the ability to perform actions independently on behalf of users or the application itself.

Default permissions, such as those granting linked third-party applications the ability to post messages, edit content, or create channels, can expose users within a workspace to cybersecurity threats. For instance, “incoming webhooks,” the technology enabling third-party apps to independently post messages on Slack channels, could be hijacked and used in phishing scams.


Misconfigurations represent a significant security risk in cloud applications, leaving data vulnerable to compromise or exposure. These errors often stem from the intricate process of configuring cloud app settings securely.

Even seasoned system administrators may find themselves grappling with the complexities of cloud app configurations, exacerbated by the uniqueness of each cloud application. 

In fact, it’s now commonplace for organizations to experience security incidents stemming from SaaS misconfigurations, with a staggering 43% reporting at least one misconfiguration-related incident within the last year.

Shadow IT

Even if your company doesn’t officially use Slack, chances are your employees are for some aspects of their work. In fact, research shows that 67% of teams employ their own collaboration tools outside of the company’s sanctioned software, a phenomenon known as shadow IT.

Shadow IT, which encompasses the use of applications, devices, and cloud services not approved by the IT department, is particularly prevalent in organizations that rely on Microsoft 365 as their primary productivity suite. Despite the collaborative features available in Microsoft Teams, some users gravitate towards Slack due to its user-friendly interface and accessibility across various devices.

While employees may have good intentions in using Slack, the associated data security risks cannot be overlooked. When IT departments lack visibility and control over data flowing through unsanctioned channels, it becomes challenging to protect sensitive information effectively. This loss of oversight can impede disaster recovery efforts, hinder data classification processes, and undermine the implementation of robust security measures.

Best practices for bolstering Slack security 

While Slack bears some responsibility for identifying and addressing vulnerabilities before they’re exploited by hackers, organizations that use the platform also have a role to play in ensuring security.

According to the shared responsibility model of the cloud, companies utilizing a SaaS application are tasked with appropriately configuring the application and managing identity and access. Essentially, it falls on you to prevent unauthorized access to employee Slack accounts.

However, achieving this goal isn’t always straightforward. Sophisticated social engineering attacks, such as the Uber incident, underscore the lengths to which attackers will go to manipulate employees into divulging their credentials or multi-factor authentication codes.

Given these challenges, it’s imperative to implement a multi-layered security strategy for Slack, encompassing the following controls.

Mandate complex passwords and two-factor authentication

It’s alarming that even in today’s advanced digital landscape, cybercriminals frequently breach companies using basic tactics, such as password reuse across multiple accounts.

Fortunately, combating this issue is straightforward. Start by instituting pass-phrases as a standard practice and prohibit employees from incorporating personal information into their passwords or reusing them across accounts.

Compliment your password policy with mandated multi-factor authentication. This ensures that, even if a password is compromised, a malicious actor won’t be able to access your employee’s Slack with a password alone. 

Apply data loss prevention policies

While Slack offers basic DLP functionality, you’ll need to invest in specialist third-party DLP tools if you want surefire protection. These tools use AI and natural language processing to automatically discover, classify and protect sensitive data in Slack, preventing incidents like unauthorized access or accidental exposure. 

Here’s a closer look at how next-generation DLP upholds Slack security: 

  • Discover lost data: From deployment, best-in-breed DLP automatically scans messages, files, and chats for unstructured data, identifying and securing all at-risk information in Slack. 
  • Meet compliance standards: A robust DLP solution will act as your virtual compliance officer, ensuring data access and usage complies with regulations like GDP and CCPA. Look for a tool that uses automation and AI to boost accuracy while preventing alert fatigue.
  • Real-time threat detection: Contextually-aware DLP solutions protect against insider threats and hijacked accounts by spotting and responding to suspicious activity instantly. For example, if a user attempts to download sensitive information from Slack, the DLP solution will block the action and alert the IT team based on a numerical risk calculation.

Embrace active learning

We suggest complementing your DLP initiative with continuous employee security training to mitigate the occurrence of human error. However, not all training methods are equally effective. Traditional approaches like away days and video tutorials often lack engagement and fail to resonate with employees.

Instead, consider implementing a more interactive form of training, such as in-app nudges. Utilized in solutions like Polymer DLP, these real-time nudges appear as pop-ups within tools like Slack. They encourage users to pause and reflect on the security impact of their actions, preventing inadvertent compromises to data security.

For instance, if an employee is on the verge of sharing a document containing sensitive data with a group, a nudge will prompt them to consider whether everyone in the group is authorized to access that data. Backed by DLP policies, our nudges not only educate employees on the importance of security but also prevent them from engaging in risky actions as needed. 

Slack: What does the future hold? 

While Slack has suffered its fair share of security incidents, it’s encouraging to see the company continue to release security updates, such as enhanced audit logging, SAML-based single sign-on and session duration limitations.

At the same time, though, Slack is pushing forward innovations of a different kind: rolling-out generative AI enhancements like AI-powered search, conversation summaries and recaps to enhance employee productivity within the platform. 

Naturally, the introduction of generative AI to Slack raises security questions. As we explore in this overview of ChatGPT risks, generative AI tools create unique security risks that organizations must contend with, such as LLM data leakage and hallucinations. 

To benefit from Slack’s innovations whilst maintaining security, it’s therefore imperative for organizations to take a proactive approach to data security, embracing specialist third-party tools like Polymer DLP that tackle the compliance and data security blind spots inherent within the platform. 

Find out more about Polymer DLP for Slack now. 


  • Does Slack have good security? Slack comes with basic security controls that should suffice if you never share sensitive data with the platform. However, most enterprises will need to use specialist third-party security solutions to enhance Slack security and meet compliance mandates. 
  • What are the security risks of Slack? Slack is vulnerable to numerous security risks, including account compromise, data leakage and social engineering attacks. 
  • Has Slack been hacked? Yes, Slack has been hacked several times over the years. The most recent incidents impacted Uber and Rockstar games, after malicious actors managed to break into the Slack Workspaces of both organizations, getting away with a wealth of sensitive data. 
  • Is data on Slack secure? Data that’s stored on Slack is vulnerable to leakage and compromise without the right security controls, including multi-factor authentication and data loss prevention. 
  • Is Slack GDPR compliant? Yes, Slack adheres to the GDPR. However, as a customer, it is also up to you to ensure your employees use Slack in a manner that complies with the GDPR.

Polymer is a human-centric data loss prevention (DLP) platform that holistically reduces the risk of data exposure in your SaaS apps and AI tools. In addition to automatically detecting and remediating violations, Polymer coaches your employees to become better data stewards. Try Polymer for free.


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