CVE-2013-3861 in .NET Framework
Summary
by MITRE
Microsoft .NET Framework 2.0 SP2, 3.5, 3.5 SP1, 3.5.1, 4, and 4.5 allows remote attackers to cause a denial of service (application crash or hang) via crafted character sequences in JSON data, aka "JSON Parsing Vulnerability."
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Analysis
by VulDB Data Team • 05/26/2021
The CVE-2013-3861 vulnerability represents a critical denial of service flaw affecting multiple versions of Microsoft .NET Framework including 2.0 SP2, 3.5, 3.5 SP1, 3.5.1, 4, and 4.5. This vulnerability specifically targets the JSON parsing functionality within these framework versions, creating a scenario where malicious actors can exploit crafted character sequences to induce application crashes or indefinite hangs. The vulnerability stems from insufficient input validation during JSON data processing, particularly when handling malformed or specially constructed character sequences that trigger unexpected behavior in the underlying parsing engine. This issue is particularly concerning given the widespread adoption of .NET Framework across enterprise applications and web services that rely heavily on JSON data exchange for communication between client and server components.
The technical flaw manifests when the .NET Framework's JSON parser encounters specific character sequences that are not properly handled during the parsing process. These sequences can cause the parser to enter an infinite loop or consume excessive system resources, leading to application instability and potential system-wide denial of service conditions. The vulnerability is classified under CWE-129 as an insufficient input validation issue, where the system fails to properly validate the bounds of input data before processing. The parsing logic in affected .NET versions does not adequately sanitize or limit the complexity of character sequences, allowing attackers to craft inputs that exploit implementation weaknesses in the JSON handling routines. This type of vulnerability falls under the ATT&CK technique T1499.004 for Network Denial of Service, where adversaries leverage software flaws to disrupt service availability.
The operational impact of CVE-2013-3861 extends beyond simple application crashes to potentially affect entire service availability and system stability. When exploited, this vulnerability can cause web applications, services, and systems running on affected .NET Framework versions to become unresponsive or crash entirely, leading to significant downtime and service disruption. The vulnerability affects both client-side applications and server-side services that process JSON data, making it particularly dangerous in enterprise environments where JSON is commonly used for API communications, web services, and data exchange protocols. Organizations utilizing .NET Framework-based applications are at risk of experiencing cascading failures if the vulnerability is exploited against critical services, potentially leading to broader system outages and business disruption. The vulnerability also poses challenges for security monitoring as the denial of service conditions may be difficult to distinguish from legitimate performance issues or other system failures.
Mitigation strategies for CVE-2013-3861 primarily focus on immediate patching and application-level protections. Microsoft released security updates that address this vulnerability through corrected JSON parsing routines and enhanced input validation mechanisms. Organizations should prioritize applying the relevant security patches as soon as possible, particularly for systems handling external JSON data inputs. Additionally, implementing input validation at application layers can provide defense-in-depth protection, where applications can sanitize JSON data before passing it to the .NET Framework parser. Network-level protections such as rate limiting and input filtering can help reduce the impact of exploitation attempts, while monitoring systems should be configured to detect unusual application behavior or resource consumption patterns that may indicate exploitation. The vulnerability highlights the importance of keeping framework components up to date and implementing comprehensive security testing procedures for JSON processing functionality within applications. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates across all affected systems and applications.