CVE-2015-8614 in Claws Mail
Summary
by MITRE
Multiple stack-based buffer overflows in the (1) conv_jistoeuc, (2) conv_euctojis, and (3) conv_sjistoeuc functions in codeconv.c in Claws Mail before 3.13.1 allow remote attackers to have unspecified impact via a crafted email, involving Japanese character set conversion.
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Analysis
by VulDB Data Team • 11/08/2024
The vulnerability CVE-2015-8614 represents a critical stack-based buffer overflow issue affecting Claws Mail email client versions prior to 3.13.1. This vulnerability specifically targets three character set conversion functions within the codeconv.c file, namely conv_jistoeuc, conv_euctojis, and conv_sjistoeuc. These functions handle the conversion between different Japanese character encodings, including JIS, EUC, and SJIS formats, which are commonly used in email communications involving Japanese text. The flaw occurs during the processing of email messages containing specially crafted Japanese character sequences that trigger buffer overflow conditions in the memory management of the application.
The technical implementation of this vulnerability stems from insufficient bounds checking in the character encoding conversion routines. When Claws Mail processes incoming emails containing malformed Japanese character sequences, the conversion functions fail to properly validate the length of input data against the allocated buffer space. This allows attackers to overflow the stack buffers and potentially overwrite adjacent memory locations, including return addresses and function pointers. The vulnerability is particularly dangerous because it can be triggered through normal email reception processes, requiring no special privileges or user interaction beyond receiving a malicious email message. The stack-based nature of the overflow means that attackers can manipulate the program execution flow by overwriting return addresses and control registers.
The operational impact of CVE-2015-8614 extends beyond simple denial of service scenarios, as the buffer overflow conditions could potentially be exploited for remote code execution. Attackers who successfully exploit this vulnerability could gain arbitrary code execution privileges on the victim's system, potentially leading to full system compromise. The unspecified impact mentioned in the CVE description reflects the wide range of potential consequences depending on the specific memory corruption patterns and the target operating system configuration. The vulnerability affects users who receive emails containing Japanese character encodings, making it particularly relevant in international email environments where such character sets are commonly used. This vulnerability aligns with CWE-121, stack-based buffer overflow, and could be categorized under ATT&CK technique T1059 for remote code execution through application vulnerabilities.
Mitigation strategies for CVE-2015-8614 primarily involve immediate software updates to Claws Mail version 3.13.1 or later, which includes proper bounds checking and memory validation in the affected character conversion functions. System administrators should implement comprehensive patch management procedures to ensure all email clients are updated promptly. Additional protective measures include implementing email filtering rules that can detect and quarantine suspicious character sequences, particularly those involving Japanese encodings. Network-level security controls such as email gateway filtering and content inspection can provide additional defense in depth. The vulnerability highlights the importance of proper input validation and memory management in internationalized applications, as character encoding conversion routines often require special attention to prevent such buffer overflow conditions. Organizations should also consider implementing automated vulnerability scanning tools to identify and remediate similar issues in other email client applications and messaging systems.