CVE-2021-22555 is a high-severity vulnerability affecting the Linux Kernel, specifically a heap out-of-bounds write discovered in the net/netfilter/x_tables.c file. This vulnerability allows an attacker to gain privileges or cause a denial of service (DoS) via heap memory corruption through user name space. With a CVSS score of 8.3, the severity of this vulnerability is significant, indicating a critical risk to organizations running affected Linux systems.
The vulnerability was published on July 7, 2021, and has since been analyzed for its impact. It is critical for organizations to understand the potential risks associated with this vulnerability, as it could lead to unauthorized access and system instability. As of now, the vulnerability is included in the Known Exploited Vulnerabilities (KEV) catalog, indicating that it is actively being exploited.
Organizations should prioritize patching immediately to protect their systems from potential exploitation. The urgency for defenders is underscored by the fact that this vulnerability has been linked to actual exploitation attempts, making it essential to take remedial actions swiftly.
In terms of remediation, organizations are advised to apply mitigations as per vendor instructions and follow applicable BOD 22-01 guidance for cloud services. If mitigations are unavailable, discontinuing the use of the affected product may be necessary.
Vulnerability Details
The vulnerability description states that a heap out-of-bounds write affecting Linux since v2.6.19-rc1 was discovered in net/netfilter/x_tables.c. The CVSS 3.1 scores reveal a base score of 8.3, indicating a high severity level. The vulnerability can be exploited over an adjacent network, which increases the risk as it requires high complexity for an attack. Notably, no privileges are required to exploit this vulnerability, and user interaction is not needed.
The affected systems include various firmware and operating system versions, notably those from NetApp and Brocade, as well as the Linux Kernel itself. The vulnerability falls under CWE-787, which relates to out-of-bounds write conditions.
Technical Analysis
The root cause of this vulnerability stems from improper handling of memory allocation in the Linux Kernel, leading to a heap out-of-bounds write condition. Attackers may leverage this vulnerability through an adjacent network, making exploitation possible without direct access to the target system. The attack complexity is assessed as high, as the attacker needs to understand kernel memory management and exploit the vulnerability correctly.
The impact on confidentiality, integrity, and availability is rated as high, meaning that successful exploitation could lead to significant consequences, including unauthorized access to sensitive data and system crashes.
Risk & Impact Analysis
The real-world risk associated with CVE-2021-22555 is substantial, as it affects multiple versions of the Linux Kernel and various products from vendors like NetApp and Brocade. Organizations running vulnerable systems are at risk of privilege escalation and denial of service, which can disrupt operations and compromise sensitive data.
The urgency assessment based on the CVSS score and known exploitation status indicates that organizations should prioritize remediation efforts. The potential blast radius of this vulnerability is extensive, impacting numerous systems and applications that utilize the affected kernel versions.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | Yes |
Ransomware Use | No |
Affected Versions
The affected versions include various Linux Kernel releases from v2.6.19 to versions prior to v4.4.267, as well as other firmware components from NetApp and Brocade. Organizations running these vulnerable systems are strongly advised to apply patches as soon as possible.
Mitigation & Remediation
Organizations should apply patches from their respective vendors to remediate CVE-2021-22555. Specific guidance includes the following actions:
1. Upgrade to the latest patched version of the Linux Kernel.
2. Consider engaging in penetration testing to validate the effectiveness of the patching process.
3. Follow applicable BOD 22-01 guidance for cloud services.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor for unusual log entries, particularly those related to kernel operations. Behavioral anomalies in system performance may indicate exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-22555 lies in its demonstration of systemic vulnerabilities within the Linux Kernel. As attackers continue to exploit these types of vulnerabilities, organizations must learn from this incident to strengthen their security posture.
Security teams should implement comprehensive vulnerability management programs and regularly conduct security assessments, including vulnerability management program design to identify and remediate similar weaknesses.
Additionally, organizations should remain vigilant regarding their patch management processes and ensure timely updates to mitigate risks associated with newly discovered vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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