CVE-2018-16131 in Akka HTTP
Summary
by MITRE
The decodeRequest and decodeRequestWith directives in Lightbend Akka HTTP 10.1.x through 10.1.4 and 10.0.x through 10.0.13 allow remote attackers to cause a denial of service (memory consumption and daemon crash) via a ZIP bomb.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability CVE-2018-16131 affects Lightbend Akka HTTP versions 10.0.x through 10.0.13 and 10.1.x through 10.1.4, specifically impacting the decodeRequest and decodeRequestWith directives. This flaw represents a significant security concern as it enables remote attackers to execute denial of service attacks through carefully crafted ZIP bomb payloads. The vulnerability stems from insufficient input validation and resource management within the HTTP request decoding mechanisms, allowing malicious actors to exploit memory consumption patterns that can lead to system instability and daemon crashes.
The technical implementation of this vulnerability involves the improper handling of compressed data during HTTP request processing. When the decodeRequest and decodeRequestWith directives encounter malformed or maliciously constructed ZIP archives, the underlying decompression logic fails to properly limit memory allocation and processing resources. This creates a scenario where a small compressed payload can expand to consume excessive memory resources, leading to memory exhaustion attacks that can crash the entire Akka HTTP daemon. The flaw operates at the application layer and can be exploited through HTTP requests containing specially crafted ZIP files that trigger the decompression routines without adequate resource constraints.
From an operational impact perspective, this vulnerability presents a critical threat to systems running affected Akka HTTP versions, as it allows attackers to cause immediate service disruption through resource exhaustion attacks. The memory consumption patterns associated with ZIP bomb exploitation can quickly overwhelm system resources, potentially affecting multiple concurrent connections and leading to complete service unavailability. Organizations relying on Akka HTTP for web services, API gateways, or backend processing systems face significant risk of operational disruption, particularly in environments where the service handles high volumes of incoming requests. The vulnerability also impacts system availability and can potentially be leveraged as part of broader attack campaigns targeting infrastructure stability.
Security practitioners should immediately upgrade to patched versions of Lightbend Akka HTTP, specifically versions 10.0.14 and 10.1.5, which contain the necessary fixes for this vulnerability. The mitigation strategy should also include implementing proper input validation, setting resource limits on decompression operations, and deploying monitoring solutions to detect unusual memory consumption patterns. Organizations should consider implementing rate limiting and request size restrictions as additional defensive measures. This vulnerability aligns with CWE-400, which covers Uncontrolled Resource Consumption, and can be mapped to ATT&CK technique T1499.001 for Network Denial of Service attacks. The fix implemented in the patched versions addresses the core issue by introducing proper resource management and validation controls within the decompression processing pipeline, preventing the exploitation of memory exhaustion patterns that previously allowed successful ZIP bomb attacks.