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CVE-2021-29441 is an authentication-bypass vulnerability in Alibaba Nacos versions before 1.4.1 when built-in authentication is enabled. Nacos's AuthFilter contains logic intended to trust requests originating from Nacos servers, based on the HTTP User-Agent value. Because this client-controlled header can be spoofed, a remote requester can impersonate a Nacos server and bypass the AuthFilter's authentication checks. The bypass permits unauthenticated access to protected Nacos administrative functionality, including creation of attacker-controlled administrative credentials.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository is a small standalone Python proof-of-concept/operational exploit for CVE-2021-29441, an authentication bypass in Alibaba Nacos before 1.4.1. The repo contains only two files: a README describing the vulnerability and exploit conditions, and a single executable script, exploit.py, which is the main entry point. The exploit works by creating a requests.Session and hardcoding the spoofed header 'User-Agent: Nacos-Server', which the vulnerable Nacos AuthFilter incorrectly trusts as an internal request marker. Using that bypass, the script interacts directly with Nacos administrative user-management APIs under /nacos/v1/auth/users. Capabilities implemented in code are broader than simple detection: it can check vulnerability by attempting to list users, enumerate existing users, create a new user with attacker-chosen credentials, delete an existing user, and update/reset a user's password. This makes it an operational exploit rather than a detection-only script. Repository structure is minimal and straightforward. README.md provides context, impact, affected versions, and remediation. exploit.py contains a NacosExploit class with helper request logic, individual methods for each administrative action, CLI argument parsing, and a main() routine. The script supports target selection, optional SSL verification disabling, and action flags (--check, --list, --create, --delete, --update-password). It prints status codes and optionally formats output with the rich library if installed. No reverse shell or post-exploitation implant is included; the payload is the crafted HTTP interaction itself. The primary security impact is unauthorized administrative access to Nacos user management over the network.
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32 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An authentication-bypass vulnerability in Nacos that can allow unauthorized access to Nacos services and APIs.
Contournement d'authentification Nacos exploité dans la campagne.
An authentication-bypass vulnerability in Nacos that can allow requests to bypass an authentication filter through a crafted User-Agent value.
A vulnerability explicitly described as weaponized by UAT-10147 during the campaign; product is not specified in the content.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.