CVE-2018-12453 in Redis
Summary
by MITRE
Type confusion in the xgroupCommand function in t_stream.c in redis-server in Redis before 5.0 allows remote attackers to cause denial-of-service via an XGROUP command in which the key is not a stream.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability CVE-2018-12453 represents a critical type confusion issue within the Redis streaming subsystem that affects versions prior to 5.0. This flaw exists in the xgroupCommand function located in t_stream.c, where the software fails to properly validate the data type of keys when processing XGROUP commands. The vulnerability stems from insufficient type checking mechanisms that allow attackers to manipulate the command execution flow by passing a key that is not actually a stream data type. This type confusion occurs because the Redis server does not verify that the target key corresponds to the expected stream type before executing stream-specific operations, creating a path for arbitrary code execution or system instability.
The technical implementation of this vulnerability involves the Redis server's stream processing logic where the xgroupCommand function assumes that all keys passed to it are of stream type without proper validation. When an attacker submits an XGROUP command with a key that references a non-stream data type such as a string or hash, the server's internal type checking mechanisms fail to detect this mismatch. This leads to memory corruption issues as the server attempts to execute stream operations on data structures that do not conform to the expected stream format. The flaw manifests as a denial-of-service condition because the type confusion causes the server to access memory locations incorrectly, potentially leading to crashes or unpredictable behavior that renders the Redis service unavailable to legitimate users.
From an operational perspective, this vulnerability presents a significant risk to Redis deployments as it allows remote attackers to cause system downtime without requiring authentication or privileged access. The attack vector is straightforward since any remote user can submit malformed XGROUP commands to the Redis server, making this a high-impact vulnerability for systems that expose Redis endpoints to untrusted networks. The vulnerability aligns with CWE-471, which describes the weakness of using an incorrect data type for a variable or parameter, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations running vulnerable Redis versions face potential service disruption, data unavailability, and may be vulnerable to cascading failures in distributed systems that depend on Redis for caching or message queuing operations.
The recommended mitigation strategy involves upgrading to Redis version 5.0 or later, which includes proper type validation for stream operations and addresses the underlying type confusion issue. System administrators should also implement network segmentation and access controls to limit exposure of Redis servers to untrusted networks, while monitoring for suspicious XGROUP command patterns that may indicate exploitation attempts. Additionally, implementing proper input validation at the application level and conducting regular security assessments of Redis configurations can help reduce the attack surface. Organizations should also consider deploying Redis instances with authentication enabled and using firewall rules to restrict access to Redis ports, as these measures provide additional layers of protection against exploitation of this vulnerability.