CVE-2020-3561 Explained : Impact and Mitigation
Learn about CVE-2020-3561, a CRLF injection vulnerability in Cisco ASA & FTD Software, allowing remote attackers to manipulate HTTP headers and redirect users to malicious sites. Find mitigation steps and long-term security practices here.
A vulnerability in the Clientless SSL VPN (WebVPN) of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to inject arbitrary HTTP headers in the responses of the affected system.
Understanding CVE-2020-3561
This CVE involves a CRLF injection vulnerability in Cisco ASA and FTD Software, potentially enabling attackers to manipulate HTTP headers.
What is CVE-2020-3561?
The vulnerability allows remote attackers to insert malicious HTTP headers into system responses by exploiting improper input sanitization, leading to potential CRLF injection attacks.
The Impact of CVE-2020-3561
If successfully exploited, attackers can add arbitrary HTTP headers to system responses, redirecting users to malicious websites without their consent.
Technical Details of CVE-2020-3561
This section provides in-depth technical insights into the vulnerability.
Vulnerability Description
The flaw arises from inadequate input sanitization in the Clientless SSL VPN (WebVPN) of Cisco ASA and FTD Software, enabling attackers to manipulate HTTP headers.
Affected Systems and Versions
- Product: Cisco Adaptive Security Appliance (ASA) Software
- Vendor: Cisco
- Versions: Not applicable (n/a)
Exploitation Mechanism
Attackers can exploit this vulnerability by tricking users into clicking on specially crafted links, initiating CRLF injection attacks.
Mitigation and Prevention
Protecting systems from CVE-2020-3561 requires immediate actions and long-term security practices.
Immediate Steps to Take
- Apply vendor-recommended patches promptly to mitigate the vulnerability.
- Educate users about phishing tactics to prevent them from clicking on malicious links.
Long-Term Security Practices
- Implement network segmentation to limit the impact of potential attacks.
- Regularly update and patch systems to address security vulnerabilities.
- Monitor network traffic for any suspicious activities.
- Conduct security awareness training for employees to enhance cybersecurity posture.
Patching and Updates
Regularly check for security advisories from Cisco and apply patches as soon as they are released to safeguard systems.