Api Key Exposure in Chi with Redis

Chi is a functional programming language for the JVM that compiles to optimized Java bytecode. When Chi services use Redis as a shared cache or session store, developers sometimes store API keys, OAuth tokens, or service credentials as plain strings in Redis keys or hash fields. Because Redis does not enforce field-level encryption by default, any process or user able to read from the cache can retrieve these sensitive values.

In a Chi application, this exposure often occurs through common patterns such as storing an API key in a Redis hash for a service client or caching an authorization token with a predictable key like apikey:stripe. If the Redis instance is reachable over the network without authentication or TLS, an attacker who can connect to the port can use commands like HGET or GET to extract the key. Even when Redis is bound to localhost, container misconfigurations or shared hosting can inadvertently expose the port, making the keys accessible.

The risk is compounded when Chi applications log or serialize Redis operations without redaction. For example, if a request handler logs the key name and the retrieved value for debugging, the secret can end up in log aggregation systems, increasing the blast radius. Because the API key is often long-lived and has broad permissions, exposure can lead to unauthorized access to third-party services, data manipulation, or financial impact.

middleBrick scans for this class of issue by checking whether endpoints or background jobs interact with Redis in ways that could leak secrets, and by correlating unauthenticated scan findings with OpenAPI definitions that describe authentication schemes. When an API uses an API key stored in Redis without additional protections, the scan can identify the weak link and map it to relevant compliance frameworks such as OWASP API Top 10 and SOC2 controls.

To illustrate a safe pattern, a Chi application can avoid placing raw keys in Redis and instead use short-lived tokens retrieved from a secure vault at runtime. If caching is necessary, store only references or hashes rather than the raw credential, and enforce network isolation and ACLs on Redis. middleBrick’s findings include specific remediation guidance, such as rotating exposed keys and enabling Redis AUTH and TLS, to reduce the likelihood of successful misuse.

Remediation focuses on preventing raw API keys from being stored in Redis and ensuring that any cached data does not expose secrets. Below are concrete examples using Chi and a Redis client such as clj-redis or using Java-based clients via interop.

First, avoid storing API keys as plain strings or hash fields. Instead, use Redis to store non-sensitive configuration or short-lived session identifiers, and keep secrets in a dedicated secrets manager. If you must cache sensitive data, encrypt it before storage.

; Chi example: store only a reference, not the raw key
(defn store-api-key-reference [redis-conn service-id key-id]
  (let [key-name (str "service:" service-id ":apikey_id")
        ;; Store only a reference; actual key is in a vault
        key-reference (str "vault:ref:" (java.util.UUID/randomUUID))]
    (redis/hset redis-conn key-name "apikey_ref" key-reference)))

If you need to retrieve a key at runtime, fetch it from a secure source and use it transiently without persisting to Redis:

; Chi example: retrieve from vault and use immediately
(defn call-external-service [service-id]
  (let [raw-key (vault/get-secret (str "service/" service-id "/apikey"))
        response (http/client {:url (str "https://api." service-id ".com/data")
                               :headers {"Authorization" (str "Bearer " raw-key)}})]
    ;; Do not log raw-key
    response))

When using Redis hashes to store non-sensitive metadata, ensure that sensitive fields are never added. Validate and sanitize all data before setting keys:

; Chi example: safe hash update for non-sensitive fields
(defn update-service-metadata [redis-conn service-id metadata]
  (redis/hset redis-conn (str "service:" service-id ":meta") metadata))

Additionally, enforce network-level protections by configuring Redis to require AUTH and using TLS. In your deployment configuration, set password-protected Redis instances and restrict bind addresses. The following is an example connection setup that enforces authentication:

; Chi example: Redis connection with password
(def redis-pool
  (redis/make-connection {:host "127.0.0.1"
                          :port 6379
                          :password (System/getenv "REDIS_PASSWORD")}))

These patterns reduce the chance of API key exposure via Redis and align with remediation guidance that middleBrick provides in its findings, which often recommend rotating keys, enabling authentication, and avoiding storage of secrets in cache layers.