CVE-2010-20113

Comprehensive Technical Analysis of CVE-2010-20113

1. Vulnerability Assessment and Severity Evaluation

CVE-2010-20113 is a critical vulnerability affecting EasyFTP Server versions 1.7.0.11 and earlier. The vulnerability is a stack-based buffer overflow in the HTTP interface, specifically when processing a GET request to list.html. The server fails to properly validate the length of the path parameter, leading to a buffer overflow that can corrupt control flow structures.

CVSS Score: 9.8

• Attack Vector (AV): Network
• Attack Complexity (AC): Low
• Privileges Required (PR): None
• User Interaction (UI): None
• Scope (S): Unchanged
• Confidentiality (C): High
• Integrity (I): High
• Availability (A): High

The high CVSS score indicates the severity of the vulnerability, which can be exploited remotely without authentication, leading to potential full system compromise.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: An attacker can send a specially crafted HTTP GET request to the vulnerable EasyFTP Server's HTTP interface.
• Anonymous Access: The vulnerability is exposed through the embedded web server, which allows default anonymous access, making it easier for attackers to exploit without needing credentials.

Exploitation Methods:

• Buffer Overflow: By sending an excessively long path parameter in the GET request to list.html, an attacker can cause a stack-based buffer overflow.
• Control Flow Corruption: The buffer overflow can corrupt control flow structures, potentially leading to arbitrary code execution.

Exploit Availability:

• Exploits are publicly available, as referenced in the Metasploit Framework and Exploit Database (EDB-ID: 11500).

3. Affected Systems and Software Versions

Affected Software:

• EasyFTP Server versions 1.7.0.11 and earlier.

Unaffected Software:

• The vulnerability was resolved in version 1.7.0.12.
• The product was subsequently renamed to UplusFtp.

4. Recommended Mitigation Strategies

Immediate Mitigation:

• Upgrade: Upgrade to EasyFTP Server version 1.7.0.12 or later.
• Disable Anonymous Access: If upgrading is not immediately possible, disable anonymous access to the HTTP interface to reduce the attack surface.

Long-Term Mitigation:

• Network Segmentation: Implement network segmentation to isolate the FTP server from other critical systems.
• Intrusion Detection Systems (IDS): Deploy IDS to monitor for suspicious HTTP GET requests targeting the list.html endpoint.
• Regular Patching: Establish a regular patching and update schedule for all software, including FTP servers.

5. Impact on Cybersecurity Landscape

Immediate Impact:

• Organizations using affected versions of EasyFTP Server are at high risk of remote code execution attacks, which can lead to data breaches, system compromise, and further lateral movement within the network.

Long-Term Impact:

• The availability of public exploits increases the likelihood of widespread attacks, emphasizing the need for timely patching and proactive security measures.
• This vulnerability highlights the importance of secure coding practices and thorough validation of user inputs to prevent buffer overflow vulnerabilities.

6. Technical Details for Security Professionals

Vulnerability Details:

• The vulnerability occurs in the HTTP interface of EasyFTP Server when processing a GET request to list.html.
• The server fails to validate the length of the path parameter, leading to a stack-based buffer overflow.
• The buffer overflow can corrupt control flow structures, potentially allowing an attacker to execute arbitrary code.

Exploit Technicalities:

• The exploit involves sending a crafted HTTP GET request with an excessively long path parameter.
• The Metasploit module exploits/windows/http/easyftp_list.rb and the Exploit Database entry (EDB-ID: 11500) provide detailed technical information and proof-of-concept code for the vulnerability.

Detection and Response:

• Detection: Monitor network traffic for unusually long HTTP GET requests targeting the list.html endpoint.
• Response: Implement incident response procedures to contain and mitigate the impact of any detected exploitation attempts.

References:

• Metasploit Framework Module
• Exploit Database Entry
• VulnCheck Advisory

By addressing this vulnerability promptly and implementing robust security measures, organizations can significantly reduce the risk of exploitation and protect their systems from potential attacks.