Slack security
No. Sharing passwords on Slack is not safe. Slack stores every message you send — including direct messages — on its servers, and that message history persists long after the conversation has moved on. A password shared in a Slack DM is not a private, fleeting exchange. It is a permanent record sitting on Slack's infrastructure, searchable, accessible to workspace administrators, and potentially visible to anyone who gains access to the account later.
Slack is a cloud-based messaging platform. Every message you send — including direct messages between two people — is stored on Slack's servers. This is not a side effect or a bug. It is how the product works. The message history is what allows you to scroll back through conversations, search across channels, and pick up where you left off on a new device.
A password you send in a Slack DM today will still be on Slack's servers in a year unless someone actively deletes it — and even then, deletion is not instant or guaranteed across all of Slack's infrastructure.
Free workspaces retain the most recent 90 days of messages. After that, older messages become inaccessible through the UI — but this does not mean they are deleted from Slack's servers.
Paid workspaces (Pro, Business+, Enterprise Grid) retain messages indefinitely by default. Organisations can configure custom retention policies, but most do not. In many professional environments, your Slack message history from two years ago is fully intact and searchable.
Enterprise Grid customers can additionally configure data export and compliance integrations, meaning third-party tools may also be retaining copies of message content.
This is the question most people do not think to ask. On Business+ and Enterprise Grid plans, workspace owners can apply to Slack for permission to export DM content. Slack's compliance export feature, when enabled, allows full message export including direct messages. Depending on your organisation's policies, this export capability may already be active.
Beyond the admin question, any third-party app or integration connected to your Slack workspace with the right permission scopes can read message content. Many workspaces have dozens of connected integrations — analytics tools, project management bridges, support ticket connectors. The practical takeaway: a Slack DM is not equivalent to a private conversation between two people.
Credential stuffing attacks — where attackers try username and password combinations leaked from other breaches — are effective precisely because most people reuse passwords. If someone on your team uses the same password for Slack as for another compromised service, an attacker who gains access to their Slack account can search the message history for credentials.
The search is trivial. Slack's search function is fast and powerful. An attacker can search for terms like “password”, “login”, “credentials”, “API key”, “access” and surface relevant messages within seconds. Every password ever shared in that workspace — in channels or DMs — is now potentially exposed.
Persistence. The message stays. You cannot unsend it from Slack's servers, and your recipient cannot delete it from their end in a way that removes it from the workspace history.
Searchability. Slack's search indexes message content. A password sitting in a DM is discoverable by anyone with sufficient access — admins, compliance tools, compromised accounts.
Channel mistakes. It is genuinely easy to send a message to the wrong Slack channel. A password intended for a private DM can end up in a public channel in seconds.
Notification previews. Slack notifications on mobile and desktop frequently show a preview of the message content. A password sent in a Slack DM may appear in a notification on the recipient's lock screen, visible to anyone nearby.
Loss of control. Once a plaintext password is in a Slack message, there is no technical barrier to it being copied, forwarded, or screenshotted.
The right approach is to never put the password in Slack at all. Generate a one-time encrypted link — the secret is encrypted in your browser before it leaves your device, stored only as ciphertext, and permanently destroyed the moment the link is opened. Send the link in Slack. The password never enters Slack's message history.
If the recipient says the link is already dead when they try to open it, that is a signal — someone else opened it first. You will know immediately and can generate a new one. For more context on work chat risks generally, see sharing passwords on work chat platforms.
Slack encrypts data in transit and at rest on their servers. However, Slack holds the encryption keys. This means Slack can decrypt and read message content — it is not end-to-end encryption in the way Signal or iMessage implement it.
You can delete the message from the Slack UI, which removes it from the visible history. However, Slack's deletion does not guarantee immediate removal from all backups, compliance archives, or third-party integrations that may have already ingested the message. Deletion is better than leaving it, but it is not a reliable security control.
Private channels restrict visibility within the workspace. But the same server-side storage, admin access, and third-party integration risks apply. Private is not the same as secure.
No. Small teams on free or Pro plans are also at risk. The difference is that smaller organisations are less likely to have security monitoring in place to detect a compromised account using Slack search to harvest credentials. The attack is just as effective on a five-person startup as on a large enterprise.
Slack stores every message. DMs are not private in the way most people assume. A password in Slack is a persistent, searchable record that outlives the conversation and can be accessed by more people than you intended. A one-time encrypted link takes 20 seconds to generate and ensures the password never enters Slack's message history at all.
Try it now
No account required. Paste a password, get a one-time link, share it in Slack.
Create a secret link →