CVE-2002-1466 in CafeLog
Summary
by MITRE
CafeLog b2 Weblog Tool 2.06pre4, with allow_fopen_url enabled, allows remote attackers to execute arbitrary PHP code via the b2inc variable.
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Analysis
by VulDB Data Team • 06/13/2018
The vulnerability identified as CVE-2002-1466 affects CafeLog b2 Weblog Tool version 2.06pre4, representing a critical remote code execution flaw that exploits a dangerous configuration setting. This vulnerability specifically targets web applications that have the allow_fopen_url PHP directive enabled, which permits the inclusion of remote files through functions like include or require. The flaw occurs when user-controllable input is passed through the b2inc variable without proper sanitization or validation, creating an avenue for malicious actors to inject and execute arbitrary PHP code on the affected server.
The technical exploitation mechanism leverages PHP's file inclusion capabilities combined with the dangerous allow_fopen_url configuration. When this setting is enabled, PHP allows remote file inclusion through functions such as include(), require(), include_once(), and require_once(). Attackers can manipulate the b2inc parameter to point to a remote malicious PHP script hosted on an attacker-controlled server, effectively bypassing local file access restrictions and gaining unauthorized code execution privileges. This represents a classic case of insecure file inclusion vulnerability that falls under the CWE-98 category for "Improper Control of Dynamic Code Features" and specifically maps to CWE-434 which addresses "Unrestricted Upload of File with Dangerous Type." The vulnerability demonstrates a fundamental failure in input validation and parameter sanitization within the application's request handling mechanism.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete control over the affected web server. Successful exploitation enables unauthorized individuals to execute arbitrary commands, potentially leading to full system compromise, data exfiltration, and persistence mechanisms. Attackers can leverage this vulnerability to install backdoors, modify existing files, create new user accounts, or even establish reverse shells for ongoing access. The vulnerability affects not only the specific weblog application but also the underlying server infrastructure, potentially compromising other applications or services running on the same host. This represents a critical threat in the ATT&CK framework under the T1059.007 technique for "Command and Scripting Interpreter: PowerShell" and T1505.003 for "Server Software Component: Web Shell," as it allows for the execution of arbitrary code through the web interface.
Mitigation strategies for CVE-2002-1466 should focus on immediate configuration changes and application-level defenses. The most effective immediate fix involves disabling the allow_fopen_url directive in the PHP configuration file, which prevents remote file inclusion attacks at the core level. Additionally, implementing strict input validation and sanitization for all user-controllable parameters, particularly those used in file inclusion operations, provides defense in depth. Application developers should employ whitelisting techniques for file inclusion parameters, validate all input against expected patterns, and implement proper access controls to limit what files can be included. The solution should also include regular security audits, input filtering mechanisms, and proper error handling to prevent information disclosure. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts, while ensuring that all software components are kept up to date with the latest security patches to prevent similar vulnerabilities from being introduced through outdated code bases.