CVE-2015-2480 in .NET Framework
Summary
by MITRE
The RyuJIT compiler in Microsoft .NET Framework 4.6 produces incorrect code during an attempt at optimization, which allows remote attackers to execute arbitrary code via a crafted .NET application, aka "RyuJIT Optimization Elevation of Privilege Vulnerability," a different vulnerability than CVE-2015-2479 and CVE-2015-2481.
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Analysis
by VulDB Data Team • 06/09/2022
The CVE-2015-2480 vulnerability represents a critical flaw in the RyuJIT compiler component of Microsoft .NET Framework 4.6 that manifests during code optimization processes. This vulnerability falls under the category of elevation of privilege attacks and is classified as a compiler bug that affects the generation of machine code. The issue specifically arises when the RyuJIT compiler attempts to optimize certain code patterns, leading to the production of incorrect executable instructions that can be exploited by remote attackers. The vulnerability is particularly concerning because it operates at the compiler level, meaning that malicious code can be injected into legitimate applications during the compilation process, potentially allowing attackers to execute arbitrary code on affected systems.
The technical root cause of this vulnerability stems from improper handling of specific optimization algorithms within the RyuJIT compiler. When the compiler processes certain combinations of instructions and data structures, it fails to correctly account for memory access patterns and register allocation during optimization phases. This flaw results in the generation of machine code that contains unexpected behavior, such as incorrect memory addressing or corrupted instruction sequences. The vulnerability is categorized under CWE-682, which deals with incorrect computation or calculation, and specifically relates to improper optimization that leads to security flaws in compiled code. The issue demonstrates how compiler-level vulnerabilities can create persistent security risks that affect all applications compiled with the affected version of the .NET Framework.
The operational impact of CVE-2015-2480 extends beyond simple privilege escalation to encompass potential full system compromise when exploited. Attackers can craft malicious .NET applications that, when compiled with the vulnerable RyuJIT compiler, will generate code that executes with elevated privileges. This vulnerability is particularly dangerous in environments where untrusted code is compiled or executed, such as cloud computing platforms, application hosting services, or any scenario where code compilation occurs on potentially compromised systems. The attack vector is primarily remote, as attackers can deliver malicious .NET applications through various channels including web applications, file downloads, or network services that process user-supplied code. This vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, as the exploitation allows for arbitrary code execution that can be used to establish persistent access or escalate privileges.
Mitigation strategies for CVE-2015-2480 focus on immediate patching and system hardening measures. Microsoft released security updates that address the vulnerability by correcting the RyuJIT compiler's optimization algorithms and preventing the generation of malformed code. Organizations should prioritize updating their .NET Framework installations to versions that contain the patched compiler, typically .NET Framework 4.6 or later with the appropriate security patches applied. Additional protective measures include implementing application whitelisting policies to restrict execution of untrusted .NET applications, disabling unnecessary compilation capabilities on servers, and monitoring for unusual code compilation activities. Network segmentation and access controls can help limit the potential impact if exploitation occurs. The vulnerability also highlights the importance of secure coding practices and code review processes, particularly when dealing with dynamic code generation or compilation scenarios. Security professionals should also consider implementing runtime monitoring solutions that can detect anomalous execution patterns that may indicate exploitation attempts.