What is CVE-2020-3452?
CVE-2020-3452 is a security vulnerability identified in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software. This vulnerability allows remote attackers to read sensitive files on the affected system by sending specially crafted directory traversal requests to the web services interface of the device. It affects multiple versions of Cisco ASA and FTD, posing a significant threat to organizations that rely on these devices for securing their networks.
CVSS Score and Severity
- CVSS Score: 7.5 (High)
- Severity: The CVSS score of 7.5 out of 10 reflects a high severity level. The ability to read sensitive files from the system without authentication makes this vulnerability a significant concern, particularly in environments where Cisco ASA and FTD devices are critical to network security.
So what’s the problem?
CVE-2020-3452 is particularly dangerous because it allows attackers to read sensitive files on the affected system without needing to authenticate. This can expose configuration files, credentials, or other critical information that could be used to further compromise the network. Given that Cisco ASA and FTD devices are often used to protect high-value assets within an organization, the potential exposure of sensitive data through this vulnerability could have severe implications for network security.
Background and Context
Background on the vulnerability
CVE-2020-3452 was discovered in 2020 and affects the web services interface of Cisco ASA and FTD devices. The vulnerability arises from improper input validation in the web interface, which fails to adequately filter directory traversal characters (e.g., ../) in incoming requests. As a result, an attacker can exploit this flaw to traverse the directory structure of the device and access sensitive files that would normally be protected.
Description of the Vulnerability (CVE-2020-3452)
The vulnerability occurs because the web services interface of Cisco ASA and FTD does not properly sanitize user input, specifically failing to prevent directory traversal attacks. An attacker can send a specially crafted URL containing directory traversal sequences to the web interface, which allows them to access files outside the intended directory. This could lead to the exposure of sensitive information, such as configuration files, SSL certificates, and other critical data stored on the device.
Root Cause Analysis
The root cause of CVE-2020-3452 is the lack of proper input validation in the web services interface of Cisco ASA and FTD devices. The interface does not adequately filter out directory traversal characters from incoming requests, allowing attackers to exploit this weakness and access files that should be protected. The vulnerability is particularly concerning in environments where the web interface is exposed to the internet or accessible by untrusted users.
Impact and Exploitation
The impact of CVE-2020-3452
Exploiting CVE-2020-3452 can have several significant impacts:
- Exposure of Sensitive Information: The primary impact is the ability for an attacker to read sensitive files stored on the device, which could include configuration files, credentials, and SSL certificates.
- Facilitation of Further Attacks: Access to sensitive files could provide the attacker with information needed to conduct further attacks, such as network intrusion, privilege escalation, or lateral movement within the network.
- Compromise of Network Security: By exposing critical information, the vulnerability could undermine the security posture of the entire network, potentially leading to broader compromise.
Exploit
To exploit CVE-2020-3452, an attacker needs to send a specially crafted HTTP request to the vulnerable web services interface of a Cisco ASA or FTD device. The exploitation process involves:
- Identifying a target Cisco ASA or FTD device with the web interface exposed to the internet.
- Crafting a URL that includes directory traversal sequences designed to access files outside the intended directory.
- Sending the crafted URL to the device, which processes the request and returns the contents of the specified file, leading to the exposure of sensitive information.
In-the-Wild Attacks
Since its disclosure, CVE-2020-3452 has been actively targeted in the wild. Attackers have exploited this vulnerability to gain unauthorized access to sensitive files on Cisco ASA and FTD devices, particularly in environments where the web interface is exposed to the internet. The vulnerability’s nature makes it a popular target for attackers seeking to gather intelligence on a network before launching further attacks.
Vulnerable code/package in the application
The vulnerable code is located within the web services interface of Cisco ASA and FTD software. The issue arises from improper input validation during the processing of incoming HTTP requests, allowing directory traversal sequences to be processed. The affected versions include various releases of Cisco ASA and FTD software that were in use before Cisco issued patches to address this vulnerability.
Statistics on vulnerability
While specific exploitation statistics for CVE-2020-3452 are not widely available, the vulnerability’s critical nature and the extensive use of Cisco ASA and FTD devices in enterprise environments make it a significant concern for organizations across various industries. The potential exposure of sensitive information underscores the importance of addressing this issue promptly.
Mitigation and Remediation
Mitigating CVE-2020-3452
Organizations can mitigate the risks associated with CVE-2020-3452 by:
- Applying Patches: Cisco has released patches to address this vulnerability. It is essential to update all affected devices to the latest software versions to prevent exploitation.
- Limiting Access to the Web Interface: Restricting access to the web services interface to trusted IP addresses or using a VPN can reduce the risk of exploitation by unauthorized users.
- Monitoring for Suspicious Activity: Implement monitoring and alerting for unusual access patterns or requests to the web interface that could indicate an attempted exploitation of the vulnerability.
Patch and Bypass: Fixes Added for CVE-2020-3452
The patch for CVE-2020-3452 involves updates to the web services interface to ensure that directory traversal characters are properly sanitized from incoming requests. This prevents attackers from accessing files outside the intended directory. Organizations should ensure that their Cisco ASA and FTD devices are updated to the latest version to protect against this vulnerability.
Proactive response
A proactive security approach includes regularly updating software, conducting security audits of network devices, and implementing best practices for securing administrative interfaces. Organizations should also consider using additional security measures such as web application firewalls (WAFs) and intrusion detection systems to monitor for suspicious activity.
Proof of Concept (POC)
A POC for CVE-2020-3452 involves sending a directory traversal request to the Cisco ASA or FTD web interface:
bash code
curl "https://<Cisco-ASA-IP>/+CSCOT+/translation-table?type=mst&textdomain=/%2e%2e/+CSCOE+/portal_inc.lua&default-language&lang=../"This request accesses a file outside the intended directory, demonstrating the directory traversal vulnerability.
Real-world Impact and Response
Timeline/changelog
- July 2020: Discovery of CVE-2020-3452 during a security review of Cisco ASA and FTD software.
- July 2020: Public disclosure of the vulnerability and release of patches by Cisco to address the issue.
- August 2020: Security advisories and guidance issued to organizations to update their devices and secure their web interfaces against potential exploitation.
- September 2020: Continued monitoring for potential exploitation and providing additional updates as needed.
Observed Activity
Since its disclosure, CVE-2020-3452 has been actively targeted by attackers, particularly in environments where Cisco ASA and FTD devices are exposed to the internet. Exploitation has led to the exposure of sensitive files, which could be used for further attacks against the network.
Mass Scanning
Following the disclosure of CVE-2020-3452, there has been an increase in scanning activity targeting Cisco ASA and FTD devices, particularly looking for systems with exposed web interfaces. Attackers use automated tools to identify and exploit vulnerable devices.
Vulnerable Server Discovery
Vulnerable devices can be discovered by attackers through targeted scanning or by analyzing network traffic for signs of outdated Cisco ASA or FTD versions. Ensuring that all devices are updated and properly configured is essential to prevent exploitation.
Reasoning and Scoring
Corporate networks impacted globally
CVE-2020-3452 has the potential to impact corporate networks globally, particularly in industries that rely heavily on Cisco ASA and FTD for network security. The vulnerability can be exploited to gain unauthorized access to sensitive information, potentially leading to broader network compromise.
Corporate numbers impacted by countries
- United States: Extensive use of Cisco ASA and FTD in enterprise environments, with many organizations potentially at risk.
- Europe: Significant adoption of Cisco security appliances in technology, finance, and critical infrastructure sectors, leading to potential exposure.
- Asia: Widespread use of Cisco ASA and FTD in industries where secure network management is critical.
Conclusion
Who should be paying attention to this?
Network administrators, cybersecurity professionals, and organizations that use Cisco ASA or FTD for network security should prioritize attention to CVE-2020-3452. Ensuring that these devices are patched and secure is critical for maintaining the integrity and confidentiality of the network.
Who is exploiting it and how?
CVE-2020-3452 has been exploited by attackers who identify vulnerable Cisco ASA or FTD devices with exposed web services interfaces. These attackers craft malicious HTTP requests designed to exploit the directory traversal vulnerability, leading to the unauthorized access of sensitive files.
How are things likely to develop?
As more organizations apply patches and secure their devices, the risk of widespread exploitation decreases. However, systems that remain unpatched are still vulnerable to attack, and the potential for targeted exploitation remains a concern. Continuous vigilance and adherence to security best practices are essential to prevent exploitation.
How long has it been around?
CVE-2020-3452 was discovered and disclosed in July 2020, but the underlying issue with improper input validation may have existed in Cisco ASA and FTD software for some time before its discovery. This highlights the importance of regular security reviews and updates to address potential vulnerabilities in critical network infrastructure.
