CVE-2009-2463 in Firefox
Summary
by MITRE
Multiple integer overflows in the (1) PL_Base64Decode and (2) PL_Base64Encode functions in nsprpub/lib/libc/src/base64.c in Mozilla Firefox before 3.0.12, Thunderbird before 2.0.0.24, and SeaMonkey before 1.1.19 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors that trigger buffer overflows.
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Analysis
by VulDB Data Team • 08/12/2021
The vulnerability identified as CVE-2009-2463 represents a critical security flaw affecting Mozilla Firefox, Thunderbird, and SeaMonkey applications prior to their respective version updates. This issue stems from integer overflows occurring within the PL_Base64Decode and PL_Base64Encode functions located in the nsprpub/lib/libc/src/base64.c file. These functions are fundamental components responsible for base64 encoding and decoding operations that are extensively utilized throughout the Mozilla ecosystem for handling various data formats including email attachments, web content, and network communications. The integer overflow conditions create a scenario where maliciously crafted input data can cause the application to allocate insufficient memory buffers, leading to memory corruption that manifests as application crashes or potentially more severe exploitation opportunities.
The technical nature of this vulnerability places it firmly within the CWE-190 category of Integer Overflow or Wraparound, which is classified as a high-severity weakness in the Common Weakness Enumeration taxonomy. This flaw specifically affects the handling of data sizes during base64 processing operations where integer variables overflow when dealing with large input values, causing the system to allocate buffers of incorrect sizes. The operational impact extends beyond simple denial of service as the vulnerability could potentially be exploited to execute arbitrary code through memory corruption techniques that manipulate the program's execution flow. Attackers could craft specially formatted base64 encoded data that, when processed by the vulnerable functions, would trigger the integer overflow conditions and subsequently corrupt memory structures.
The exploitation vectors for this vulnerability are particularly concerning as they can be triggered through various user interactions including opening malicious email attachments in Thunderbird, visiting compromised web pages in Firefox, or processing malformed data in SeaMonkey applications. The memory corruption resulting from these integer overflows creates opportunities for attackers to manipulate heap memory structures, potentially leading to code execution under the privileges of the affected application. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as the memory corruption could enable attackers to inject and execute malicious code within the application context. The severity of the impact is compounded by the fact that these applications are widely used across different operating systems and environments, making the vulnerability particularly attractive to threat actors seeking to exploit a large attack surface.
Mitigation strategies for CVE-2009-2463 primarily involve updating to the patched versions of the affected Mozilla applications. Mozilla released versions 3.0.12 for Firefox, 2.0.0.24 for Thunderbird, and 1.1.19 for SeaMonkey that address the integer overflow conditions in the base64 processing functions. System administrators should prioritize immediate deployment of these security updates across all affected systems. Additionally, network administrators can implement defensive measures such as monitoring for unusual base64 encoded data patterns in network traffic and implementing web application firewalls that can detect and block malicious base64 inputs. Organizations should also consider implementing principle of least privilege for email and web browsing applications to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the importance of proper input validation and integer overflow protection in cryptographic and data processing functions, reinforcing the need for comprehensive security testing and code review processes to identify similar weaknesses in application code.