CVE-2008-7265 in ProFTPD
Summary
by MITRE
The pr_data_xfer function in ProFTPD before 1.3.2rc3 allows remote authenticated users to cause a denial of service (CPU consumption) via an ABOR command during a data transfer.
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Analysis
by VulDB Data Team • 05/23/2025
The vulnerability described in CVE-2008-7265 represents a significant denial of service weakness within the ProFTPD server implementation that affects versions prior to 1.3.2rc3. This flaw specifically targets the pr_data_xfer function which handles data transfer operations within the FTP protocol. The vulnerability manifests when authenticated remote users exploit the ABOR command during active data transfer sessions, creating a condition where the server consumes excessive CPU resources. The issue stems from insufficient input validation and improper handling of asynchronous abort commands during transfer operations, leading to a scenario where the server becomes unresponsive to legitimate requests while consuming disproportionate computational resources. This type of vulnerability falls under the category of resource exhaustion attacks that can severely impact service availability and system performance.
The technical implementation of this vulnerability involves the pr_data_xfer function failing to properly terminate or handle data transfer operations when an ABOR command is received. When an authenticated user sends an ABOR command during an active data transfer, the function does not correctly process the abort signal, resulting in a loop or excessive processing that consumes CPU cycles. The flaw demonstrates poor error handling and state management within the FTP server's data transfer mechanism, where the system fails to gracefully handle the interruption of ongoing operations. This behavior creates a condition where the server's CPU utilization spikes dramatically, potentially leading to complete service unavailability for other legitimate users attempting to access the FTP service. The vulnerability specifically targets the server's ability to manage concurrent operations and properly handle user interruption signals during file transfers.
From an operational impact perspective, this vulnerability poses a serious threat to the availability and reliability of FTP services hosted on affected ProFTPD servers. The denial of service condition can be triggered by any authenticated user with access to the FTP service, making it particularly dangerous in environments where user access controls may be compromised or where multiple users share the same server instance. The CPU consumption issue can escalate rapidly, potentially causing the server to become unresponsive or crash entirely, disrupting legitimate file transfer operations for all users. Organizations relying on ProFTPD for file sharing services may experience significant downtime, loss of productivity, and potential business disruption. The vulnerability also demonstrates how seemingly routine FTP commands can be exploited to create substantial system impact, highlighting the importance of proper input validation and error handling in network service implementations.
The mitigation strategy for CVE-2008-7265 requires immediate deployment of ProFTPD version 1.3.2rc3 or later, which includes patches addressing the improper handling of ABOR commands during data transfers. System administrators should also implement network monitoring to detect unusual CPU consumption patterns that may indicate exploitation attempts. Additional protective measures include implementing access controls to limit FTP access to trusted users only, configuring rate limiting for FTP commands, and establishing automated alerting for abnormal resource utilization. This vulnerability aligns with CWE-400, which categorizes resource exhaustion issues, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing intrusion detection systems that can identify and block suspicious FTP command sequences that may indicate exploitation attempts. The fix implemented in the patched version ensures proper state management and graceful handling of abort signals during data transfer operations, preventing the CPU consumption anomaly that characterized the original vulnerability.