Covert Channel Subscription Vulnerability in @bellaxchuu/flowblue Package
Summary
MAL-2026-17345: Malicious code in @bellaxchuu/flowblue (npm). Affects @bellaxchuu/flowblue versions 1.5.7. No fix is published. How to fix ↓
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Background
The @bellaxchuu/flowblue package is a fork of the Baileys WhatsApp Web library, designed to facilitate interactions with WhatsApp's API. It is part of a larger family of similar packages that have been identified as potentially malicious. This package allows developers to build applications that can send and receive messages on WhatsApp, but it has been compromised to include malicious code that exploits users' authenticated sessions.
Vulnerability Detail
The vulnerability arises from malicious code embedded within the @bellaxchuu/flowblue package. This code injects a covert channel-subscription action into the WhatsApp socket layer, allowing attackers to silently subscribe the victim's account to channels without their consent. The attack utilizes the installer's authenticated WhatsApp session to issue a FOLLOW query to attacker-controlled channels. The target JIDs are obfuscated using various techniques, making it difficult for users to detect the malicious behavior. Although this vulnerability does not exfiltrate credentials or execute arbitrary code, it can lead to unwanted subscriptions and potential privacy concerns.
How To Fix
This package is malicious. Remove it and rotate any credentials it could have accessed.
npm uninstall @bellaxchuu/flowblueIf it arrived as a transitive dependency, remove the package that pulled it in, then reinstall.
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Workaround
As a temporary workaround, you can remove the @bellaxchuu/flowblue package from your project by executing the following command: npm uninstall @bellaxchuu/flowblue. This will prevent the malicious code from executing until a safe version is available.
Conclusion
The @bellaxchuu/flowblue package contains a serious vulnerability that allows attackers to exploit users' authenticated WhatsApp sessions. It is crucial for developers to take immediate action by updating or removing the package to protect their applications and users from potential risks.
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FAQ
The vulnerability involves malicious code that subscribes users to WhatsApp channels without their consent, using their authenticated session.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. Check your application using the Vulert playground at Vulert Scanner.
You should uninstall the package immediately and check for any updates or patches that may address the vulnerability.
No, the vulnerability does not exfiltrate credentials, but it does misuse your authenticated session for malicious purposes.
The main consequence is unwanted subscriptions to channels, which can lead to spam and privacy concerns for the affected users.
References
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