CVE-2006-3013 in phpBannerExchange
Summary
by MITRE
Interpretation conflict in resetpw.php in phpBannerExchange before 2.0 Update 6 allows remote attackers to execute arbitrary SQL commands via an email parameter containing a null (%00) character after a valid e-mail address, which passes the validation check in the eregi PHP command. NOTE: it could be argued that this vulnerability is due to a bug in the eregi PHP command and the proper fix should be in PHP; if so, then this should not be treated as a vulnerability in phpBannerExchange.
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Analysis
by VulDB Data Team • 07/29/2018
The vulnerability described in CVE-2006-3013 represents a sophisticated SQL injection attack vector within the phpBannerExchange application's resetpw.php component. This flaw emerged in versions prior to 2.0 Update 6 and demonstrates a critical interpretation conflict that bypasses standard input validation mechanisms. The attack exploits a specific quirk in how the eregi PHP function processes input containing null characters, creating a scenario where malicious payloads can circumvent security checks designed to validate email addresses.
The technical exploitation occurs when an attacker crafts an email parameter that includes a valid email address followed by a null character represented as %00. This particular sequence passes the validation check implemented through the eregi function, which exhibits inconsistent behavior when processing null-terminated strings. The vulnerability stems from the fundamental mismatch between the validation logic and the actual execution context where SQL commands are processed, allowing attackers to inject malicious SQL code that gets executed within the database context.
From an operational perspective, this vulnerability presents a severe risk to systems running affected versions of phpBannerExchange as it enables remote attackers to execute arbitrary SQL commands without authentication. The implications extend beyond simple data theft to include potential system compromise, data manipulation, and unauthorized access to sensitive information stored within the application's database. The attack requires minimal sophistication and can be automated, making it particularly dangerous in environments where the application handles user registration or password recovery functions.
The vulnerability aligns with CWE-89 which categorizes SQL injection flaws as weaknesses in software that allows attackers to manipulate database queries through untrusted input. This specific variant also relates to ATT&CK technique T1190 which describes exploiting vulnerabilities in web applications to gain access to backend systems. The exploitation pathway demonstrates how seemingly benign validation functions can create dangerous security gaps when they fail to account for all possible input interpretations, particularly in legacy PHP implementations where functions like eregi exhibited inconsistent behavior with special characters.
Organizations should implement immediate mitigations including upgrading to phpBannerExchange version 2.0 Update 6 or later, which contains the necessary fixes for this vulnerability. Additionally, input validation should be strengthened to explicitly filter out null characters and other special sequences that could be exploited in similar contexts. The remediation process should also involve reviewing all input validation logic throughout the application to identify potential similar vulnerabilities that might arise from inconsistent handling of special characters in string processing functions.