SlackPirate: How a Single Stolen Cookie Can Compromise Every Workspace You Access
Hook
A single cookie value—just one—can grant an attacker access to every Slack workspace you’ve ever joined. SlackPirate automates the extraction of everything sensitive hiding in those workspaces.
Context
Slack’s meteoric rise to over 8 million customers by 2018 created a sprawling attack surface that many security teams still haven’t properly addressed. Unlike email or file servers that typically fall under strict governance, Slack workspaces often operate in a gray zone—deployed by individual teams, integrated with dozens of services, and filled with years of unaudited conversations. Developers paste API keys for quick sharing. DevOps engineers share AWS credentials in ‘private’ channels. Legal teams upload confidential documents. All of this lives indefinitely in a searchable, API-accessible database.
SlackPirate emerged as a post-exploitation tool designed for this exact scenario. Once an attacker obtains valid credentials—whether through phishing, stolen session tokens, or insider access—they face the tedious task of manually combing through thousands of messages and files. SlackPirate automates this reconnaissance phase by systematically querying Slack’s native APIs to extract credentials, private keys, S3 bucket references, and sensitive documents. It’s equally valuable for blue teams conducting security audits to discover what secrets are lurking in their own workspaces before attackers do.
Technical Insight
SlackPirate’s architecture exploits a critical characteristic of Slack’s authentication model: the ‘d’ cookie. While most web applications use session cookies scoped to a single domain or application instance, Slack’s ‘d’ cookie works across all workspaces a user has access to. This design decision—likely made for user convenience to avoid repeated logins—creates a powerful attack primitive. Steal one cookie, access every workspace.
The tool operates in two modes. First, you can provide just the ‘d’ cookie to enumerate accessible workspaces and extract their associated API tokens:
python3 SlackPirate.py --cookie d=xoxd-aBcDeFg1234567890...This reconnaissance phase connects to each workspace and extracts workspace-specific tokens (which start with ‘xoxc-’). The README indicates these tokens can be found in the form data of requests sent to Slack’s API or by scraping process memory. Once you have a token, you pair it with the cookie to run the extraction modules:
python3 SlackPirate.py --cookie d=xoxd-aBcDeFg1234567890... --token xoxc-1234567890-9876543210-abcdefghijkThe tool then validates the token, checks for elevated privileges (admin, owner, primary_owner), and launches its scanning modules. Each module targets specific patterns through Slack’s native APIs. The S3 scanner searches for bucket URL patterns across all accessible channels and direct messages. The credentials scanner looks for AWS access keys (AKIA…), secret keys, password assignments in code snippets, and private key headers (-----BEGIN RSA PRIVATE KEY-----).
The tool also scans for pinned messages across channels, links to external services (Google Docs, Trello invites, internal systems), and downloads files matching predefined keywords like .key, .sh, or documents containing ‘password’ or ‘secret’. Additionally, if the provided token has admin privileges, it can dump team access logs and user lists in JSON format.
The interactive mode deserves special attention. Rather than memorizing command-line flags, you can run:
python3 SlackPirate.py --interactiveThis launches a console UI that prompts for tokens and cookies, then presents a menu of available scan modules. You can selectively enable or disable specific scanners—useful when you want to run only the S3 enumeration module:
python3 SlackPirate.py --token <token> --s3-scanOr exclude specific modules:
python3 SlackPirate.py --token <token> --no-s3-scanOutput can be dumped in JSON format by default, or in more detailed CSV format using the —verbose flag, which includes additional context like channel names, usernames, and permalinks. This allows offline analysis without maintaining persistent connections to the target workspace.
Gotcha
SlackPirate’s biggest limitation is right in the name: it’s a pirate, not a lockpick. You need valid credentials before it does anything useful. This isn’t an initial access tool—it won’t help you break into a Slack workspace. You need to have already obtained a valid ‘d’ cookie and ideally a workspace token through phishing, physical access, or compromising a user’s machine. For red teams, this means SlackPirate sits in the post-exploitation phase, not reconnaissance.
The pattern-matching approach also has inherent blindspots. The tool searches for predefined patterns like ‘AKIA’ for AWS access keys or ‘-----BEGIN’ for private keys. If a developer base64-encoded their credentials, obfuscated them in unusual formats, or used non-standard naming conventions, SlackPirate will miss them entirely. You’ll also get false positives—mentions of ‘password’ in documentation or discussions about security will trigger alerts alongside actual credentials. The tool doesn’t have semantic understanding; it’s pure pattern matching.
Another consideration: both the cookie and token are required for the tool to authenticate properly. The README explicitly states ‘Make sure to pass in both a token and a cookie - you need both to be able to authenticate.’ The tool has been tested on Python 3.5, 3.6, and 3.7, with noted compatibility issues on Python 2, so ensure you’re running a supported Python version. The README dates the Slack customer count to May 2018, suggesting the tool was developed around that timeframe, though basic Slack API endpoints it relies on likely remain functional.
Verdict
Use SlackPirate if you have authorized access to a Slack workspace and need to audit it for exposed secrets—whether you’re a penetration tester with stolen credentials simulating an attacker, or a blue team member conducting security awareness training by demonstrating what’s extractable. It excels at the tedious work of systematically scanning messages and files that would take significant time to review manually. The interactive mode makes it accessible even if you’re not comfortable with command-line tools, and the modular scanner selection lets you tune which scans to run. Skip it if you lack initial access credentials (you need both a ‘d’ cookie and workspace token), need real-time monitoring rather than point-in-time extraction, or require guaranteed zero false positives—the pattern-matching approach will require manual triage of results. Also consider that the tool was developed around 2018 based on README context, so verify compatibility with current Slack API versions for your specific use case. For real-time monitoring or more sophisticated analysis, consider custom implementations using official Slack SDKs or general-purpose secret scanners like truffleHog applied to Slack exports.
