CVE-2018-19518 Scanner

PHP imap is a versatile toolkit utilized predominantly in UNIX systems for handling IMAP connections. It is implemented in various web applications to facilitate email retrieval and processing. Developers employ this kit to streamline connections to email servers, optimizing communication through IMAP functionalities. Its integration in PHP expands its utility, allowing it to be embedded in web applications for email manipulation. The software is robust and widely distributed, enjoying significant use in systems requiring email management. Its adoption spans both personal projects and enterprise-level applications due to its comprehensive feature set and ease of integration.

The vulnerability lies in the University of Washington IMAP Toolkit's handling of command inputs within its imap_open() in PHP. It allows remote command execution through inadequate argument handling when interfacing with the system's rsh or its replacements. This flaw can be exploited if the IMAP server name contains malicious input, leading to potential arbitrary OS command execution. Attackers could leverage this behavior particularly where rsh is replaced by ssh, enabling severe exploitation scenarios. The vulnerability is surreptitiously dangerous if these commands are not scrutinized properly, posing a significant risk. Its exploitability gains prominence in environments where input validation is lax, potentially compromising system integrity.

The vulnerability technically arises from improper handling of server names processed via the imap_rimap function. The tcp_aopen function, when executed, lacks safeguards against argument injection, leading to vulnerabilities. Exploitation involves tailoring inputs that manipulate expected argument sequences, enabling unintended OS command execution. The flaw is identified in scenarios where parameters are not correctly sanitized, leading to bypassing of input constraints. This vulnerability is notable in systems misconfigured to handle command manipulations naively. In particular, the PHP imap toolkit's insecurities manifest under these conditions, exhibiting a clear pathway to execution vulnerabilities.

If exploited, this vulnerability could have far-reaching implications for affected systems. It could grant attackers unauthorized access to perform arbitrary command execution, leading to potential data breaches and loss of data integrity. Additionally, systems could encounter service disruption or be leveraged in broader attack strategies, compromising network security. The attack vector could extend to enabling backdoors, data exfiltration, and unauthorized control over system operations. Organizations using this setup could face significant security risks, heightened further in networked environments. As such, addressing this vulnerability is crucial to maintaining operational security and data confidentiality.

REFERENCES

• https://github.com/vulhub/vulhub/tree/master/php/CVE-2018-19518
• https://nvd.nist.gov/vuln/detail/CVE-2018-19518
• https://www.openwall.com/lists/oss-security/2018/11/22/3
• https://github.com/Bo0oM/PHP_imap_open_exploit/blob/master/exploit.php