Header Injection in Apache Camel Kafka Component

Executive Summary

This vulnerability affects the Apache Camel camel-kafka component and involves improper input validation and neutralization of special elements, specifically header injection. The issue arises because certain Kafka header constants like kafka.OVERRIDE_TOPIC are not prefixed with 'CamelKafka' and thus bypass HTTP header filtering. This allows an attacker to set these headers via an HTTP client, causing messages to be published to arbitrary Kafka topics instead of the intended configured topic.

As a result, an attacker can redirect messages to sensitive internal topics or inject malicious messages into critical downstream services. Other headers like kafka.OVERRIDE_TIMESTAMP and kafka.PARTITION_KEY can also be manipulated to backdate messages or target specific partitions. This vulnerability exists in Apache Camel versions from 4.0.0 before 4.14.8, 4.15.0 before 4.18.3, and 4.19.0 before 4.21.0.

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Impact Analysis

This vulnerability can have significant impacts including unauthorized redirection of Kafka messages to sensitive internal topics, which may lead to data exposure or leakage.

It also allows injection of attacker-crafted messages into Kafka topics consumed by critical downstream services, potentially causing data corruption, service disruption, or unauthorized actions.

Manipulation of message timestamps and partition keys can further disrupt message processing order or targeting, affecting system reliability and integrity.

No authentication is required when the bridging consumer is unauthenticated, increasing the risk of exploitation.

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Detection Guidance

Detection of this vulnerability involves monitoring for the presence of kafka.* headers, such as kafka.OVERRIDE_TOPIC, in HTTP requests or messages that are routed to the camel-kafka producer component.

You can inspect incoming HTTP headers or Kafka message headers for suspicious kafka.* prefixed headers that should not be present or are being set by untrusted sources.

• Use network packet capture tools (e.g., tcpdump or Wireshark) to filter HTTP traffic and look for headers starting with kafka.
• On the system running Apache Camel, use logging or debugging features to log incoming headers and check for kafka.* headers.
• If you have access to the Camel routes, add logging steps to output headers before the kafka: producer endpoint.
• Example command to capture HTTP traffic and filter for kafka headers: tcpdump -A -s 0 'tcp port 80 or tcp port 443' | grep -i 'kafka.'

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Mitigation Strategies

The primary mitigation is to upgrade Apache Camel to a fixed version: 4.14.8, 4.18.3, or 4.21.0 depending on your release stream.

If immediate upgrade is not possible, implement a temporary mitigation by stripping kafka.* headers from any untrusted ingress before the kafka: producer endpoint.

• Add a step in your Camel route to remove headers matching 'kafka.*' from incoming messages, for example: removeHeaders('kafka.*') at the start of the route.
• Set the target Kafka topic from a trusted source rather than allowing it to be overridden by incoming headers.

After upgrading, update routes to use the new CamelKafka-prefixed header names (e.g., CamelKafkaOverrideTopic) instead of the old kafka.* headers to ensure proper filtering.

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