CVE-2024-35223 in Dapr
Summary
by MITRE • 05/23/2024
Dapr is a portable, event-driven, runtime for building distributed applications across cloud and edge. Dapr sends the app token of the invoker app instead of the app token of the invoked app. This causes of a leak of the application token of the invoker app to the invoked app when using Dapr as a gRPC proxy for remote service invocation. This vulnerability impacts Dapr users who use Dapr as a gRPC proxy for remote service invocation as well as the Dapr App API token functionality. An attacker could exploit this vulnerability to gain access to the app token of the invoker app, potentially compromising security and authentication mechanisms. This vulnerability was patched in version 1.13.3.
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Analysis
by VulDB Data Team • 05/23/2024
The vulnerability described in CVE-2024-35223 represents a critical authentication flaw within the Dapr distributed application runtime that fundamentally undermines the security model of service-to-service communication. Dapr serves as a portable event-driven runtime designed to simplify building distributed applications across cloud and edge environments, providing essential capabilities including service invocation, state management, and pub/sub messaging. The flaw manifests specifically when Dapr functions as a gRPC proxy for remote service invocation, where the system incorrectly forwards the authentication token of the calling application rather than the token of the target application. This misconfiguration creates a direct pathway for token leakage that violates fundamental security principles of identity management and access control. The vulnerability directly impacts the core App API token functionality of Dapr, which is essential for maintaining secure communication between microservices in distributed architectures.
The technical implementation of this flaw stems from improper token handling within Dapr's service invocation mechanism when operating in gRPC proxy mode. When an application invokes another service through Dapr's gRPC proxy, the system should ensure that the target service receives authentication credentials that validate its own identity rather than those of the calling service. However, the vulnerability causes Dapr to inadvertently expose the invoker's application token to the invoked service, creating a scenario where the target application gains access to the authentication context of the calling application. This represents a clear violation of the principle of least privilege and creates a significant attack surface where malicious actors could potentially leverage stolen tokens to impersonate legitimate applications within the distributed system. The flaw operates at the application layer and specifically affects the gRPC communication protocol implementation within Dapr's service invocation framework.
The operational impact of this vulnerability extends beyond simple token leakage to encompass potential compromise of entire distributed application security models. An attacker exploiting this vulnerability could gain unauthorized access to applications that rely on Dapr for secure service invocation, potentially leading to data breaches, privilege escalation, and unauthorized system access. The implications are particularly severe for organizations using Dapr in production environments where multiple applications communicate through the same proxy infrastructure, as a single compromised token could provide access to multiple services within the application ecosystem. This vulnerability directly affects the integrity of Dapr's authentication mechanisms and could enable attackers to perform unauthorized service invocations, access protected resources, or manipulate application state through legitimate service endpoints. The security implications align with CWE-284 (Improper Access Control) and CWE-306 (Missing Authentication) categories, as the flaw creates unauthorized access paths and undermines authentication mechanisms.
Organizations using Dapr in gRPC proxy mode should immediately implement mitigation strategies to address this vulnerability. The primary recommended action is to upgrade to Dapr version 1.13.3, which contains the necessary patches to correct the token handling behavior. Additionally, security teams should conduct comprehensive audits of their Dapr deployments to identify any applications that may be affected by this vulnerability, particularly those relying on service invocation patterns through gRPC proxies. Network segmentation and monitoring should be enhanced to detect any suspicious token usage patterns or unauthorized service access attempts. Implementing additional authentication layers, such as mutual TLS certificates, can provide defense-in-depth measures while the upgrade is being deployed. The vulnerability's exploitation requires an attacker to have access to the Dapr service invocation infrastructure, making it a targeted issue that affects specific deployment patterns rather than general Dapr functionality. This aligns with ATT&CK technique T1566 (Phishing) and T1071.004 (Application Layer Protocol: DNS) when considering how attackers might gain access to the affected infrastructure, though the core vulnerability lies in the improper token handling rather than network-level attacks.