CVE-2019-25014 in Istio Pilot
Summary
by MITRE • 01/29/2021
A NULL pointer dereference was found in pkg/proxy/envoy/v2/debug.go getResourceVersion in Istio pilot before 1.5.0-alpha.0. If a particular HTTP GET request is made to the pilot API endpoint, it is possible to cause the Go runtime to panic (resulting in a denial of service to the istio-pilot application).
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Analysis
by VulDB Data Team • 02/21/2021
The vulnerability identified as CVE-2019-25014 represents a critical null pointer dereference flaw within the Istio pilot component, specifically affecting versions prior to 1.5.0-alpha.0. This issue resides in the pkg/proxy/envoy/v2/debug.go file within the getResourceVersion function, where improper input validation leads to a runtime panic condition. The vulnerability manifests when a specially crafted HTTP GET request is sent to the pilot API endpoint, exploiting a fundamental flaw in the application's error handling mechanisms. The root cause stems from the absence of proper null checks before dereferencing pointers, creating an execution path where the Go runtime encounters a nil reference that cannot be handled gracefully, resulting in application termination.
This vulnerability directly maps to CWE-476 which defines NULL Pointer Dereference as a condition where a null pointer is dereferenced, leading to program termination or unexpected behavior. The attack vector involves an external actor sending malformed HTTP requests to the pilot service, which operates as a core component in Istio's service mesh architecture responsible for managing traffic routing and proxy configuration. The operational impact of this flaw extends beyond simple service disruption, as it affects the entire Istio control plane's stability and reliability, potentially compromising the network infrastructure that relies on consistent proxy behavior for traffic management.
The denial of service condition created by this vulnerability can have cascading effects throughout the service mesh ecosystem, as the istio-pilot component serves as a central coordination point for all proxy instances in the mesh. When the pilot service crashes due to the null pointer dereference, it disrupts the entire traffic management infrastructure, causing proxy instances to lose connectivity to the control plane and potentially leading to service outages across the entire mesh. This vulnerability aligns with ATT&CK technique T1499.004 which describes Network Denial of Service attacks targeting network infrastructure components.
Mitigation strategies for this vulnerability require immediate patching to versions 1.5.0-alpha.0 or later where the null pointer dereference has been addressed through proper input validation and defensive programming practices. Organizations should implement network segmentation and access controls to limit exposure of the pilot API endpoints to untrusted networks, while also deploying monitoring solutions to detect anomalous HTTP request patterns that may indicate exploitation attempts. Additionally, implementing circuit breaker patterns and graceful degradation mechanisms within the Istio deployment can help maintain service availability even when individual components experience issues, ensuring that the overall system remains resilient against such denial of service conditions.