CVE-2007-5622 in 3proxy
Summary
by MITRE
Double free vulnerability in the ftpprchild function in ftppr in 3proxy 0.5 through 0.5.3i allows remote attackers to cause a denial of service (daemon crash) via multiple OPEN commands to the FTP proxy.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/29/2019
The CVE-2007-5622 vulnerability represents a critical double free memory corruption issue within the 3proxy FTP proxy software version 0.5 through 0.5.3i. This vulnerability specifically affects the ftpprchild function in the ftppr component of the proxy daemon, creating a scenario where remote attackers can manipulate the application's memory management behavior to trigger a denial of service condition. The flaw manifests when multiple OPEN commands are issued to the FTP proxy, exploiting improper memory handling mechanisms that lead to the same memory block being freed twice, a classic memory corruption pattern that can result in application instability and crash.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the FTP proxy's child process handling mechanism. When the ftpprchild function processes multiple OPEN commands, it fails to properly track memory allocations and deallocations, resulting in a situation where a memory pointer is passed to the free() function twice. This double free condition creates a heap corruption state that can be exploited by remote attackers to cause the proxy daemon to crash, effectively rendering the service unavailable to legitimate users. The vulnerability operates at the application layer and requires no authentication or special privileges, making it particularly dangerous as it can be exploited by anyone with network access to the affected FTP proxy service.
From an operational impact perspective, this vulnerability creates significant disruption potential for organizations relying on 3proxy FTP services, as it enables remote attackers to perform denial of service attacks that can take systems offline without requiring any privileged access or complex exploitation techniques. The attack vector is straightforward, requiring only the ability to send multiple OPEN commands to the FTP proxy, which can be accomplished through automated tools or manual intervention. This makes the vulnerability particularly attractive to attackers seeking to disrupt services, as the exploitation process is both simple and effective. Organizations using affected versions of 3proxy face the risk of service interruption, potential data loss during crashes, and increased operational overhead from having to manage and recover from these attacks.
Mitigation strategies for CVE-2007-5622 should prioritize immediate software updates to versions that have patched the double free vulnerability, as this represents the most effective approach to addressing the root cause. Organizations should also implement network-level controls such as firewall rules that restrict access to FTP proxy services to trusted networks only, reducing the attack surface available to remote adversaries. Additionally, monitoring systems should be configured to detect unusual patterns of OPEN command usage that might indicate exploitation attempts, enabling rapid response to potential attacks. The vulnerability aligns with CWE-415, which specifically addresses double free conditions in memory management, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Regular security assessments and vulnerability scanning should be conducted to identify other potential memory corruption issues in legacy proxy software, while implementing proper input validation and memory management practices in all network services to prevent similar vulnerabilities from emerging in future deployments.