CVE-2018-25025 in actix-web Crate
Summary
by MITRE • 12/27/2021
An issue was discovered in the actix-web crate before 0.7.15 for Rust. It can unsoundly extend the lifetime of a string, leading to memory corruption.
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Analysis
by VulDB Data Team • 12/30/2021
The vulnerability identified as CVE-2018-25025 represents a critical memory safety issue within the actix-web crate version 0.7.14 and earlier, affecting Rust applications that utilize this web framework. This flaw manifests as an unsound lifetime extension mechanism that permits improper memory management during string handling operations. The issue stems from the crate's inability to properly enforce Rust's ownership and lifetime semantics, creating conditions where string references may persist beyond their valid memory allocation periods. Such behavior fundamentally undermines the memory safety guarantees that Rust is designed to provide, making applications susceptible to various forms of memory corruption and potentially exploitable conditions.
The technical implementation of this vulnerability occurs within the actix-web crate's string handling mechanisms where it permits the extension of string lifetimes in ways that violate Rust's safety guarantees. Specifically, the flaw allows developers to create references to string data that may be deallocated or moved elsewhere in memory, resulting in use-after-free conditions or dangling pointer dereferences. This unsound extension of lifetimes can occur during request processing or response generation when string data is manipulated or passed between different components of the web framework. The vulnerability is particularly dangerous because it operates at the compiler level where Rust's safety mechanisms should prevent such operations, yet the crate's implementation bypasses these protections through unsafe code patterns that extend string lifetimes beyond their intended scope.
The operational impact of CVE-2018-25025 extends beyond simple memory corruption to potentially enable remote code execution in vulnerable applications. When exploited, this vulnerability can lead to arbitrary code execution on systems running affected versions of actix-web, making it particularly dangerous for web applications that process untrusted input from external sources. The memory corruption that results from this flaw can manifest as application crashes, data corruption, or more severe security implications when combined with other exploitation techniques. Applications using affected versions of the crate are at risk of experiencing denial of service conditions, data leakage, or complete system compromise depending on the execution context and the nature of the input being processed. The vulnerability affects not only the immediate application but also potentially the entire hosting environment if proper sandboxing mechanisms are not in place.
Mitigation strategies for CVE-2018-25025 require immediate upgrading to actix-web version 0.7.15 or later, which contains the necessary fixes to address the unsound lifetime extension issue. Organizations should conduct comprehensive vulnerability assessments to identify all systems running affected versions of the crate and prioritize patching efforts accordingly. Additionally, developers should review their codebases for any custom implementations that might rely on similar unsafe lifetime extension patterns and refactor these components to comply with Rust's ownership model. Security monitoring should be enhanced to detect potential exploitation attempts, and application-level protections such as address space layout randomization and stack canaries should be implemented as additional defensive measures. The vulnerability aligns with CWE-467 and CWE-471 categories related to improper handling of string lifetimes and unsound type conversions, and represents a clear violation of ATT&CK technique T1059.001 for command and script injection through memory corruption vulnerabilities.