CVE-2003-0307 in Poster
Summary
by MITRE
Poster version.two allows remote authenticated users to gain administrative privileges by appending the "|" field separator and an "admin" value into the email address field.
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Analysis
by VulDB Data Team • 05/17/2019
The vulnerability described in CVE-2003-0307 represents a critical access control flaw in the Poster version.two application that enables authenticated remote attackers to escalate their privileges to administrative level. This issue stems from improper input validation and sanitization within the email address field processing mechanism, creating a path for privilege escalation attacks that can be exploited without requiring additional authentication credentials beyond initial access. The vulnerability specifically manifests when attackers append a pipe character followed by the string "admin" to their email address during the registration or profile update process, effectively bypassing normal authentication controls.
The technical root cause of this vulnerability aligns with CWE-285, which addresses improper authorization within software applications, and more specifically with CWE-347, concerning improper verification of cryptographic signatures or certificates. The flaw operates through a classic input manipulation attack vector where the application fails to properly sanitize user-provided email addresses before processing them in authorization contexts. The pipe character acts as a field separator in the application's internal processing logic, allowing attackers to inject additional administrative parameters that are then interpreted as legitimate administrative commands. This type of vulnerability falls under the ATT&CK technique T1078.004, which covers valid accounts with administrative privileges, and T1548.001, covering abuse of privileges through elevation of privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the application's security model and can lead to complete system compromise. Once an attacker gains administrative access through this method, they can modify user accounts, access sensitive data, alter system configurations, and potentially establish persistent backdoors. The vulnerability affects any authenticated user within the Poster version.two system, making it particularly dangerous as it can be exploited by individuals who may have legitimate access to the system but lack administrative privileges. The attack requires minimal technical expertise and can be automated, making it attractive to both malicious actors and penetration testers seeking to assess system security.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization measures at all levels of the application stack. The most effective approach involves implementing strict email address validation that rejects special characters such as the pipe symbol, while also ensuring that user inputs are properly escaped or encoded before being processed in authorization contexts. Organizations should implement proper access control mechanisms that do not rely on simple string matching or concatenation of user inputs, instead utilizing secure authentication frameworks that properly separate user data from authorization logic. Additionally, regular security audits and input validation testing should be conducted to identify similar vulnerabilities in legacy systems, with the implementation of web application firewalls that can detect and block such injection attempts. The vulnerability demonstrates the critical importance of secure coding practices and proper input sanitization, as outlined in the OWASP Top Ten security principles, particularly the prevention of injection attacks and the enforcement of proper access controls.