CVE-2015-2505 in Exchange Server
Summary
by MITRE
Outlook Web Access (OWA) in Microsoft Exchange Server 2013 Cumulative Update 8 and 9 and SP1 allows remote attackers to obtain sensitive stacktrace information via a crafted request, aka "Exchange Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 06/14/2022
The CVE-2015-2505 vulnerability represents a critical information disclosure flaw within Microsoft Exchange Server's Outlook Web Access component, specifically affecting versions 2013 Cumulative Update 8 and 9 as well as Service Pack 1. This vulnerability resides in the web-based email interface that millions of enterprise users rely upon for accessing their corporate email systems, making it a prime target for cyber adversaries seeking to gather intelligence about the underlying infrastructure. The flaw manifests when the OWA service processes malformed requests that trigger internal error handling mechanisms, resulting in the exposure of sensitive stack trace information to remote attackers. The vulnerability is classified under CWE-200, which specifically addresses the exposure of sensitive information to an unauthorized actor, making it a direct violation of fundamental security principles that govern information protection.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP requests sent to the Exchange Server's web interface, where attackers can craft specific payloads that cause the server to generate and return detailed error messages containing stack trace information. These stack traces typically include internal file paths, method names, class structures, and potentially sensitive system information that can reveal the underlying architecture and implementation details of the Exchange Server environment. The vulnerability operates at the application layer and does not require authentication to exploit, making it particularly dangerous as it can be leveraged by threat actors without prior access credentials. The flaw essentially represents a failure in proper error handling and input validation, where the application does not adequately sanitize user-supplied data before processing it through internal error reporting mechanisms.
The operational impact of CVE-2015-2505 extends far beyond simple information disclosure, as the exposed stack trace data can provide attackers with critical insights into the internal workings of the Exchange infrastructure. This information can be leveraged for subsequent attacks, including but not limited to, exploitation of other vulnerabilities within the same system, social engineering campaigns targeting specific employees, or reconnaissance for more sophisticated attack vectors. The vulnerability aligns with ATT&CK technique T1212, which involves exploitation of information disclosure vulnerabilities to gather intelligence about target systems. Security professionals have noted that this type of information exposure can facilitate privilege escalation attacks or serve as a stepping stone for more comprehensive breaches, particularly when combined with other reconnaissance data gathered from the exposed system components.
Mitigation strategies for this vulnerability require immediate application of Microsoft security patches and updates, specifically targeting the cumulative updates and service packs that address this specific flaw. Organizations should implement network segmentation to limit access to Exchange servers and consider implementing web application firewalls to filter malicious requests before they reach the vulnerable components. The vulnerability also underscores the importance of proper error handling practices and input validation within web applications, as recommended by OWASP Top Ten and other security frameworks. Additionally, security monitoring should be enhanced to detect unusual patterns of error reporting or excessive logging that might indicate exploitation attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the email infrastructure, while incident response procedures should be updated to address potential exploitation of information disclosure vulnerabilities. The remediation process should also include comprehensive network monitoring to detect any attempts to exploit the vulnerability and ensure that all Exchange servers are properly patched and maintained according to Microsoft's security update schedule.