CVE-2013-2197 in Login Security
Summary
by MITRE
The Login Security module 6.x-1.x before 6.x-1.3 and 7.x-1.x before 7.x-1.3 for Drupal, when using the login delay option, allows remote attackers to cause a denial of service (CPU consumption) via a large number of failed login attempts.
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Analysis
by VulDB Data Team • 03/18/2019
The vulnerability described in CVE-2013-2197 affects the Login Security module for Drupal content management systems, specifically versions 6.x-1.x before 6.x-1.3 and 7.x-1.x before 7.x-1.3. This issue represents a significant security concern that can be exploited to compromise system availability through resource exhaustion attacks. The vulnerability manifests when the login delay option is enabled, which is a defensive mechanism designed to slow down brute force login attempts by introducing artificial delays between failed authentication requests. However, the implementation contains a critical flaw that allows attackers to circumvent this protection mechanism and consume excessive system resources.
The technical flaw lies in how the module handles failed login attempts when the delay feature is active. Instead of properly managing the rate limiting and resource allocation, the system fails to effectively throttle the processing of multiple concurrent failed login attempts. This creates a scenario where an attacker can flood the system with numerous simultaneous failed login requests, causing the server to consume excessive cpu cycles and memory resources as it attempts to process each delayed response. The vulnerability directly relates to CWE-400, which categorizes the issue as an Uncontrolled Resource Consumption problem, where the system fails to properly limit resource usage under attack conditions. The flaw essentially transforms a protective mechanism designed to prevent brute force attacks into a vector for denial of service exploitation.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire web application infrastructure. When exploited, the vulnerability can cause significant cpu utilization spikes that may lead to system instability, application crashes, or complete service unavailability for legitimate users. Attackers can leverage this weakness to perform sustained denial of service attacks against Drupal installations that have the Login Security module enabled, making it particularly dangerous in production environments where system uptime is critical. The vulnerability affects systems that rely on the module's login delay functionality as a security control, creating a paradoxical situation where the very feature meant to protect against unauthorized access becomes a tool for system compromise. This issue demonstrates the importance of proper resource management in security controls and highlights how defensive mechanisms can be subverted if not carefully implemented.
Mitigation strategies for CVE-2013-2197 involve multiple layers of protection and system hardening approaches. The primary recommendation is to upgrade to the patched versions of the Login Security module, specifically versions 6.x-1.3 and 7.x-1.3, which contain the necessary fixes to properly handle concurrent failed login attempts. Organizations should also implement additional network-level protections such as rate limiting at the firewall or load balancer level to prevent the overwhelming number of requests from reaching the vulnerable application servers. The use of intrusion detection systems can help identify and alert on unusual login patterns that may indicate exploitation attempts. From a defensive standpoint, implementing proper access control measures including account lockout policies, two-factor authentication, and monitoring of login activities can reduce the effectiveness of such attacks. This vulnerability aligns with ATT&CK technique T1499.004, which covers Network Denial of Service, and demonstrates how seemingly beneficial security controls can be exploited when implementation flaws exist. System administrators should also consider implementing application-level rate limiting and monitoring to detect and prevent excessive resource consumption patterns that could indicate exploitation of this vulnerability.