CVE-2017-14062 in Libidn2
Summary
by MITRE
Integer overflow in the decode_digit function in puny_decode.c in Libidn2 before 2.0.4 allows remote attackers to cause a denial of service or possibly have unspecified other impact.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-14062 represents a critical integer overflow flaw within the Libidn2 library's puny_decode.c component. This issue affects versions prior to 2.0.4 and stems from improper handling of integer arithmetic within the decode_digit function. The vulnerability manifests when processing internationalized domain names that utilize the Punycode encoding scheme, which is essential for representing non-ASCII characters in domain names within the internet infrastructure. The integer overflow occurs during the decoding process where the software fails to properly validate input parameters, leading to potential memory corruption or unexpected behavior.
The technical implementation of this vulnerability involves the decode_digit function which processes digit characters during Punycode decoding operations. When maliciously crafted input data is processed through this function, the integer overflow can cause the program to allocate insufficient memory or perform invalid memory operations. This flaw falls under the Common Weakness Enumeration category CWE-190, which specifically addresses integer overflow conditions that can lead to memory corruption and arbitrary code execution. The vulnerability is particularly concerning because it operates at the core decoding mechanism of internationalized domain name processing, making it a potential attack vector for disrupting DNS resolution services and web applications that rely on proper domain name handling.
From an operational impact perspective, this vulnerability can be exploited by remote attackers to trigger denial of service conditions within systems that utilize Libidn2 for domain name processing. The potential for unspecified other impacts suggests that beyond simple service disruption, attackers might be able to manipulate program execution flow or access sensitive memory regions. The attack surface extends across any application or service that depends on Libidn2 for handling internationalized domain names, including web servers, email systems, and network infrastructure components that process DNS queries. This vulnerability directly impacts the stability and reliability of internet infrastructure components that handle internationalized domain names, potentially affecting millions of users who rely on proper domain name resolution services.
The mitigation strategy for this vulnerability requires immediate upgrading to Libidn2 version 2.0.4 or later, which contains the necessary patches to prevent integer overflow conditions in the decode_digit function. Organizations should conduct comprehensive vulnerability assessments to identify all systems utilizing Libidn2 and ensure proper patch management protocols are in place. Additionally, network monitoring should be enhanced to detect potential exploitation attempts through malformed domain name requests. The ATT&CK framework categorizes this vulnerability under the T1210 technique for exploiting known vulnerabilities, highlighting the importance of maintaining up-to-date software libraries and implementing robust input validation mechanisms. System administrators should also consider implementing network segmentation and access controls to limit potential attack vectors and reduce the impact of successful exploitation attempts.