A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
The severity level of this vulnerability is classified as high, with a CVSS score of 8.6, indicating a significant risk to organizations. The potential for exploitation is considerable due to the low complexity of the attack and the lack of required privileges or user interaction. Organizations using affected Cisco products need to be vigilant regarding their security posture and the implications of this vulnerability.
Risk to organizations includes service disruption that could affect business continuity. Given that this vulnerability allows for remote attacks, the urgency for defenders to address it is high. Organizations should prioritize patching immediately to mitigate this risk.
Currently, there is no public exploit confirmed, and the vulnerability is not part of the Known Exploited Vulnerabilities (KEV) catalog. Nevertheless, the potential for an attacker to exploit this weakness necessitates immediate attention.
Vulnerability Details
The vulnerability identified as CVE-2021-1573 affects the Cisco Adaptive Security Appliance and Firepower Threat Defense Software, specifically in the web services interface. It allows unauthenticated remote attackers to cause a denial of service. The vulnerability is due to insufficient input validation during HTTPS request parsing. When successfully exploited, it can lead to device reloads and service interruptions.
The CVSS score for this vulnerability is as follows: 8.6 (high severity) from Cisco and 7.5 (high severity) from NVD. The impact on availability is marked as high due to the potential service disruptions caused by successful attacks.
The affected components include the adaptive security appliance and firepower threat defense. The vulnerability is present in versions up to 9.7 for ASA Software and 6.2.2 for FTD Software.
Technical Analysis
The root cause of CVE-2021-1573 stems from improper input validation when processing HTTPS requests. Attackers can exploit this vulnerability through network access without requiring any privileges or user interaction. The attack complexity is low, making it easier for malicious actors to execute a denial of service attack.
The attack vector is network-based, meaning that exploitation can occur remotely without physical access to the device. The implications for confidentiality and integrity are minimal, as the primary impact lies in the availability of the service.
Risk & Impact Analysis
Organizations utilizing the affected Cisco products should assess the real-world deployment risk associated with CVE-2021-1573. The potential for service interruption is significant, which can lead to operational challenges and financial losses.
Organizations should prioritize addressing this vulnerability as part of their patch management process, considering its high CVSS score and the implications of availability impact. The urgency assessment indicates that remediation should be part of the priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions for Cisco Adaptive Security Appliance Software are all versions prior to 9.7, and for Cisco Firepower Threat Defense Software, it includes versions up to 6.2.2. Specific vulnerable ranges also include certain versions within the 6.2.x and 9.x series.
Mitigation & Remediation
Organizations should prioritize patching to the latest versions of Cisco Adaptive Security Appliance and Firepower Threat Defense Software to address this vulnerability. For those unable to apply patches immediately, temporary workarounds might include enhanced input validation controls and implementing network segmentation to minimize exposure.
For continuous security assessments, organizations might consider using continuous penetration testing to identify potential vulnerabilities before they can be exploited.
Detection Guidance
To detect signs of exploitation attempts, organizations should monitor logs for unusual HTTPS request patterns targeting the affected devices. Behavioral anomalies such as unexpected service reboots or increased network traffic may indicate potential attacks.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-1573 lies in the growing trend of exploiting vulnerabilities in web services that can lead to denial of service. Security teams should learn from this incident to enhance their defenses against similar vulnerabilities.
This vulnerability represents a pattern of increasing risk in networked systems where improper input validation is prevalent. Organizations should regularly review their security controls and implement best practices to mitigate risks.
For further insights on vulnerability management and security practices, organizations can explore our resources on vulnerability management programs and effective penetration testing methodologies to strengthen your organization's security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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