CVE-2019-3888 in Web Server
Summary
by MITRE
A vulnerability was found in Undertow web server before 2.0.21. An information exposure of plain text credentials through log files because Connectors.executeRootHandler:402 logs the HttpServerExchange object at ERROR level using UndertowLogger.REQUEST_LOGGER.undertowRequestFailed(t, exchange)
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Analysis
by VulDB Data Team • 10/05/2023
The vulnerability identified as CVE-2019-3888 resides within the Undertow web server implementation prior to version 2.0.21, representing a critical information exposure flaw that compromises the confidentiality of sensitive authentication data. This vulnerability manifests through improper logging practices where the web server inadvertently persists plain text credentials in log files, creating a persistent security risk for systems utilizing this software component. The flaw specifically occurs within the Connectors.executeRootHandler method at line 402, where the HttpServerExchange object is logged at ERROR level using the UndertowLogger.REQUEST_LOGGER.undertowRequestFailed method, thereby exposing sensitive information to unauthorized parties who may access these log files.
The technical exploitation of this vulnerability stems from the web server's logging mechanism that fails to sanitize or redact authentication credentials before writing them to log files. When an error condition occurs during request processing, the HttpServerExchange object contains unmasked credentials that are subsequently written to the error logs in plain text format. This represents a direct violation of security best practices and demonstrates a failure in proper input validation and output sanitization within the logging subsystem. The vulnerability falls under the Common Weakness Enumeration category CWE-209, which specifically addresses "Information Exposure Through an Error Message," and more broadly relates to CWE-532, "Information Exposure Through Log Data." The flaw enables attackers to obtain valid authentication credentials simply by accessing the web server's log files, which typically contain extensive debugging information for operational troubleshooting.
From an operational perspective, this vulnerability creates significant risk for organizations deploying Undertow web servers, as it allows for credential compromise without requiring network-level attacks or complex exploitation techniques. The exposure occurs automatically during normal server operation when error conditions arise, making the vulnerability particularly dangerous since it can be exploited by any entity with access to the server's file system or log file locations. Attackers can leverage this weakness to gain unauthorized access to protected resources, potentially leading to full system compromise, data breaches, or lateral movement within network environments. The impact extends beyond immediate credential theft to include potential compliance violations under various regulatory frameworks such as pci dss, hipaa, and gdpr, which mandate protection of sensitive authentication information.
Mitigation strategies for CVE-2019-3888 primarily involve upgrading the Undertow web server to version 2.0.21 or later, which includes proper credential sanitization in logging operations. Organizations should also implement comprehensive log management practices including regular log file access controls, automated log rotation, and monitoring for unauthorized access attempts to log directories. Additionally, security configurations should enforce strict file permissions on log files to prevent unauthorized users from accessing sensitive information. The remediation aligns with ATT&CK framework technique T1562.006, "Impair Command History Logging," as proper logging practices are essential for maintaining system integrity and security monitoring. Organizations should also consider implementing centralized logging solutions with proper log filtering capabilities to prevent sensitive data from being written to log files in the first place, thereby providing defense-in-depth against similar information exposure vulnerabilities.