CVE-2021-35539 in Solaris
Summary
by MITRE • 10/20/2021
Vulnerability in the Oracle Solaris product of Oracle Systems (component: Filesystem). The supported version that is affected is 11. Easily exploitable vulnerability allows low privileged attacker with logon to the infrastructure where Oracle Solaris executes to compromise Oracle Solaris. While the vulnerability is in Oracle Solaris, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle Solaris. CVSS 3.1 Base Score 6.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H).
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Analysis
by VulDB Data Team • 10/27/2021
The vulnerability identified as CVE-2021-35539 represents a significant availability risk within Oracle Solaris 11 operating system, specifically within the filesystem component. This weakness manifests as a buffer overflow condition that occurs during certain filesystem operations, allowing an attacker with low privileges to execute malicious code that can cause system instability. The vulnerability's classification as easily exploitable indicates that the attack surface is relatively accessible, requiring only a basic level of system access to initiate exploitation attempts. The CVSS 3.1 score of 6.5 reflects the moderate to high severity impact on system availability, with the availability impact rating of "H" demonstrating the potential for complete system denial of service.
The technical flaw stems from improper input validation within the filesystem subsystem of Oracle Solaris 11, where insufficient bounds checking occurs during file operations that process user-supplied data. This vulnerability falls under the CWE-121 category of stack-based buffer overflow, though it may also exhibit characteristics of heap-based buffer overflows depending on the specific exploitation vector. Attackers can leverage this weakness by crafting malicious filesystem operations that exceed the allocated buffer space, causing memory corruption that leads to system crashes or hangs. The low privilege requirement means that even users with minimal system access can potentially compromise the entire operating environment, making this vulnerability particularly dangerous in multi-user systems.
Operational impact assessment reveals that successful exploitation of CVE-2021-35539 can result in complete system downtime, affecting not only the targeted Oracle Solaris environment but potentially impacting connected systems that depend on its services. The vulnerability's potential to cause repeated crashes or hangs creates a persistent availability threat that can disrupt business operations and compromise critical infrastructure services. Organizations running Oracle Solaris 11 systems may experience significant downtime during exploitation attempts, with recovery requiring system restarts and potential forensic analysis to determine the extent of compromise. The CVSS vector analysis indicates that this vulnerability can be exploited from a local network access point with low attack complexity, minimal privileges required, and can cause a significant security impact across the entire system.
Mitigation strategies should include immediate deployment of Oracle's security patches and updates to address the identified buffer overflow condition in the filesystem component. System administrators should implement network segmentation to limit local access points and reduce the attack surface available to potential adversaries. Regular monitoring of system logs for unusual filesystem activity and crash patterns can help identify exploitation attempts before they cause complete system failure. The vulnerability's classification under the ATT&CK framework would place it within the system compromise and privilege escalation domains, requiring comprehensive security monitoring and incident response procedures. Organizations should also consider implementing additional security controls such as mandatory access controls, file integrity monitoring, and regular security assessments to prevent exploitation of similar vulnerabilities in the filesystem subsystem.