Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. Due to the improper URL protocols filtering of links specified in the `link.argocd.argoproj.io` annotations in the application summary component, an attacker can achieve cross-site scripting with elevated permissions. All unpatched versions of Argo CD starting with v1.0.0 are vulnerable to a cross-site scripting (XSS) bug allowing a malicious user to inject a javascript: link in the UI. When clicked by a victim user, the script will execute with the victim's permissions (up to and including admin). This vulnerability allows an attacker to perform arbitrary actions on behalf of the victim via the API, such as creating, modifying, and deleting Kubernetes resources. A patch for this vulnerability has been released in Argo CD versions v2.10.3 v2.9.8, and v2.8.12. There are no completely-safe workarounds besides upgrading. The safest alternative, if upgrading is not possible, would be to create a Kubernetes admission controller to reject any resources with an annotation starting with link.argocd.argoproj.io or reject the resource if the value use an improper URL protocol. This validation will need to be applied in all clusters managed by ArgoCD.
Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. The Argo CD API prior to versions 2.10-rc2, 2.9.4, 2.8.8, and 2.7.15 are vulnerable to a cross-server request forgery (CSRF) attack when the attacker has the ability to write HTML to a page on the same parent domain as Argo CD. A CSRF attack works by tricking an authenticated Argo CD user into loading a web page which contains code to call Argo CD API endpoints on the victim’s behalf. For example, an attacker could send an Argo CD user a link to a page which looks harmless but in the background calls an Argo CD API endpoint to create an application running malicious code. Argo CD uses the “Lax” SameSite cookie policy to prevent CSRF attacks where the attacker controls an external domain. The malicious external website can attempt to call the Argo CD API, but the web browser will refuse to send the Argo CD auth token with the request. Many companies host Argo CD on an internal subdomain. If an attacker can place malicious code on, for example, https://test.internal.example.com/, they can still perform a CSRF attack. In this case, the “Lax” SameSite cookie does not prevent the browser from sending the auth cookie, because the destination is a parent domain of the Argo CD API. Browsers generally block such attacks by applying CORS policies to sensitive requests with sensitive content types. Specifically, browsers will send a “preflight request” for POSTs with content type “application/json” asking the destination API “are you allowed to accept requests from my domain?” If the destination API does not answer “yes,” the browser will block the request. Before the patched versions, Argo CD did not validate that requests contained the correct content type header. So an attacker could bypass the browser’s CORS check by setting the content type to something which is considered “not sensitive” such as “text/plain.” The browser wouldn’t send the preflight request, and Argo CD would happily accept the contents (which are actually still JSON) and perform the requested action (such as running malicious code). A patch for this vulnerability has been released in the following Argo CD versions: 2.10-rc2, 2.9.4, 2.8.8, and 2.7.15. The patch contains a breaking API change. The Argo CD API will no longer accept non-GET requests which do not specify application/json as their Content-Type. The accepted content types list is configurable, and it is possible (but discouraged) to disable the content type check completely. Users are advised to upgrade. There are no known workarounds for this vulnerability.
Argo CD is a declarative continuous deployment for Kubernetes. All versions of ArgoCD starting from v2.4 have a bug where the ArgoCD repo-server component is vulnerable to a Denial-of-Service attack vector. Specifically, the said component extracts a user-controlled tar.gz file without validating the size of its inner files. As a result, a malicious, low-privileged user can send a malicious tar.gz file that exploits this vulnerability to the repo-server, thereby harming the system's functionality and availability. Additionally, the repo-server is susceptible to another vulnerability due to the fact that it does not check the extracted file permissions before attempting to delete them. Consequently, an attacker can craft a malicious tar.gz archive in a way that prevents the deletion of its inner files when the manifest generation process is completed. A patch for this vulnerability has been released in versions 2.6.15, 2.7.14, and 2.8.3. Users are advised to upgrade. The only way to completely resolve the issue is to upgrade, however users unable to upgrade should configure RBAC (Role-Based Access Control) and provide access for configuring applications only to a limited number of administrators. These administrators should utilize trusted and verified Helm charts.
Argo CD is a declarative continuous deployment for Kubernetes. Argo CD Cluster secrets might be managed declaratively using Argo CD / kubectl apply. As a result, the full secret body is stored in`kubectl.kubernetes.io/last-applied-configuration` annotation. pull request #7139 introduced the ability to manage cluster labels and annotations. Since clusters are stored as secrets it also exposes the `kubectl.kubernetes.io/last-applied-configuration` annotation which includes full secret body. In order to view the cluster annotations via the Argo CD API, the user must have `clusters, get` RBAC access. **Note:** In many cases, cluster secrets do not contain any actually-secret information. But sometimes, as in bearer-token auth, the contents might be very sensitive. The bug has been patched in versions 2.8.3, 2.7.14, and 2.6.15. Users are advised to upgrade. Users unable to upgrade should update/deploy cluster secret with `server-side-apply` flag which does not use or rely on `kubectl.kubernetes.io/last-applied-configuration` annotation. Note: annotation for existing secrets will require manual removal.