CVE-2021-20046 is a high-severity vulnerability affecting SonicWall's SonicOS, specifically impacting Gen 5, Gen 6, and Gen 7 firmware versions. This vulnerability allows for a stack-based buffer overflow in the HTTP Content-Length response header. A remote authenticated attacker can exploit this flaw to cause a Denial of Service (DoS) and potentially gain the ability to execute arbitrary code within the firewall.
The CVSS score for this vulnerability is 8.8, indicating a high severity level. This score reflects the potential impact on confidentiality, integrity, and availability, all rated as high. Therefore, it poses a significant risk to organizations using affected SonicWall devices.
Organizations should prioritize patching this vulnerability immediately, as it can be exploited remotely without requiring user interaction. Additionally, the potential for code execution exacerbates the situation, making it imperative to address this issue swiftly.
The urgency for remediation is heightened by the fact that this vulnerability has not been included in the Known Exploit Vulnerability (KEV) catalog, suggesting that it may not yet be actively exploited in the wild, but the risk remains significant.
Vulnerability Details
The official description from SonicWall states: 'A Stack-based buffer overflow in the SonicOS HTTP Content-Length response header allows a remote authenticated attacker to cause Denial of Service (DoS) and potentially results in code execution in the firewall.' The vulnerability is categorized under CWE-121 (Stack-based Buffer Overflow) and CWE-787 (Out-of-bounds Write).
The vulnerability affects all versions of SonicOS prior to 7.0.1-r146 and 7.0.1-5023-1349. SonicWall has advised users to apply the necessary patches to mitigate the risk associated with this vulnerability.
Technical Analysis
The root cause of CVE-2021-20046 is related to improper handling of the HTTP Content-Length header in SonicOS, which leads to a stack-based buffer overflow. The attack vector is through the network, with low complexity, requiring low privileges for exploitation, and no user interaction is necessary.
Successful exploitation could lead to a complete compromise of the firewall, impacting confidentiality, integrity, and availability. The vulnerability's impact is rated as high, emphasizing the need for immediate attention from organizations using affected SonicWall products.
Risk & Impact Analysis
Risk to organizations includes potential loss of control over network security, as attackers may exploit this vulnerability to gain unauthorized access or disrupt services. The blast radius is considerable, given that firewalls are critical components in network security architecture.
Organizations should assess their exposure and prioritize the application of available patches. Given the high CVSS score, rapid remediation is essential, particularly for environments where SonicWall devices are deployed in critical roles.
In light of the current threat landscape, where network devices are increasingly targeted, organizations must remain vigilant and proactive in their security posture.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of SonicOS prior to 7.0.1-r146 and 7.0.1-5023-1349 are vulnerable to CVE-2021-20046. Organizations should ensure they are running the latest firmware to mitigate potential risks.
Mitigation & Remediation
Organizations should apply the latest patches provided by SonicWall to remediate this vulnerability. For those unable to patch immediately, consider implementing network controls to limit exposure of the affected devices.
Further, it is advisable to conduct a thorough security assessment to identify potential weaknesses in the network and apply configuration hardening measures to safeguard against exploitation.
Organizations should validate remediation through continuous penetration testing to identify similar weaknesses.
Detection Guidance
Monitoring network logs for unusual patterns related to HTTP header fields can help identify potential exploitation attempts. Additionally, security teams should be alert for any behavioral anomalies that could indicate a compromise.
AppSecure Threat Intelligence Insight
CVE-2021-20046 highlights the ongoing need for organizations to remain vigilant about vulnerabilities affecting critical infrastructure components like firewalls. The stack-based buffer overflow nature of this vulnerability underscores the importance of secure coding practices and regular security assessments.
Security teams should also evaluate their incident response capabilities to effectively address vulnerabilities as they arise, ensuring that they are equipped to mitigate risks associated with potential exploits.
For further reading on vulnerability management best practices, consider reviewing our vulnerability management program and how it can help in proactive defense strategies.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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