CVE-2018-25024 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 coerce an immutable reference into a mutable reference, leading to memory corruption.
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Analysis
by VulDB Data Team • 12/30/2021
The vulnerability identified as CVE-2018-25024 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 exists in the core memory management mechanisms of the crate and demonstrates a fundamental weakness in how immutable references are handled within the runtime environment. The issue stems from the crate's ability to perform unsafe coercions between reference types, creating a pathway for memory corruption that can compromise the integrity of running applications.
This memory corruption vulnerability arises from unsound coercion practices that allow the system to transform immutable references into mutable ones without proper safety checks. The technical implementation involves the crate's internal handling of reference types where the compiler's safety guarantees are bypassed through unsafe code patterns. When an immutable reference is coerced into a mutable reference, it creates a scenario where multiple mutable references to the same memory location can exist simultaneously, violating Rust's ownership model and leading to undefined behavior. This type of flaw falls under CWE-466, which specifically addresses the use of unsafe operations that can lead to memory corruption through improper reference handling.
The operational impact of this vulnerability extends beyond simple memory corruption to potentially enable more sophisticated attacks including arbitrary code execution and denial of service conditions. Attackers who can manipulate the conditions that trigger this coercion can exploit the memory corruption to overwrite critical data structures, corrupt heap metadata, or even execute malicious code within the application's memory space. The vulnerability is particularly dangerous in web applications where input validation and memory safety are paramount, as it can be triggered through crafted requests that manipulate the web framework's internal reference management. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where memory corruption can be leveraged to execute arbitrary code through compromised application processes.
The mitigation strategy for CVE-2018-25024 requires immediate upgrading to actix-web version 0.7.15 or later, which contains the necessary fixes to prevent the unsafe coercion of references. Organizations should also conduct thorough code reviews to identify any custom implementations that might be relying on similar unsafe patterns, as the vulnerability could potentially exist in application code that interacts with the affected crate. Additionally, implementing comprehensive memory safety testing including fuzzing and static analysis tools can help detect similar issues in other components of the application stack. The fix implemented in version 0.7.15 addresses the root cause by ensuring proper validation of reference types and preventing the unsound coercion that previously led to memory corruption, thereby restoring the memory safety guarantees that Rust's ownership model is designed to provide.