CVE-2015-1822 in chrony
Summary
by MITRE
chrony before 1.31.1 does not initialize the last "next" pointer when saving unacknowledged replies to command requests, which allows remote authenticated users to cause a denial of service (uninitialized pointer dereference and daemon crash) or possibly execute arbitrary code via a large number of command requests.
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Analysis
by VulDB Data Team • 05/09/2022
The vulnerability identified as CVE-2015-1822 affects the chrony time synchronization daemon version 1.31.1 and earlier, representing a critical flaw in the handling of command request responses. This issue stems from improper memory management practices within the daemon's implementation, specifically in how it processes and stores unacknowledged replies to command requests. The root cause lies in the failure to properly initialize the "next" pointer field when creating data structures to store these unacknowledged replies, creating a scenario where uninitialized memory values are subsequently dereferenced during normal operational procedures.
The technical exploitation of this vulnerability occurs through authenticated remote attackers who can submit a large volume of command requests to the chrony daemon. When the daemon processes these requests, it creates entries for unacknowledged replies without properly initializing the memory pointer fields. This uninitialized pointer dereference can lead to unpredictable behavior including daemon crashes and system instability. The vulnerability's potential for arbitrary code execution arises from the fact that the uninitialized memory values may contain data that, when interpreted as a pointer address, could redirect execution flow to malicious code locations, particularly when the daemon attempts to traverse linked data structures containing these corrupted pointers.
The operational impact of CVE-2015-1822 extends beyond simple denial of service conditions, as it represents a potential pathway for privilege escalation and system compromise. In environments where chrony is running with elevated privileges to manage system time synchronization, an attacker could leverage this vulnerability to gain unauthorized access to the system. The vulnerability affects systems where chrony serves as a time synchronization service, particularly in enterprise environments, cloud infrastructures, and any networked systems relying on precise timekeeping for security operations. This flaw directly violates the principle of least privilege and memory safety practices, as outlined in common weakness enumeration cwe-457 and aligns with attack techniques described in the attack tree framework where initial access through command injection leads to privilege escalation through memory corruption.
Mitigation strategies for CVE-2015-1822 primarily focus on immediate patch deployment to upgrade chrony to version 1.31.1 or later, which contains the necessary memory initialization fixes. Organizations should also implement network segmentation and access controls to limit the number of authenticated users who can submit command requests to chrony services. Additional defensive measures include monitoring for unusual command request patterns and implementing intrusion detection systems that can identify potential exploitation attempts. System administrators should conduct thorough vulnerability assessments to identify all systems running affected chrony versions and establish regular patch management procedures. The vulnerability demonstrates the importance of proper memory management practices and adherence to secure coding standards, particularly when dealing with linked data structures and pointer manipulation in daemon processes. This issue highlights the critical need for comprehensive code review processes and automated memory checking tools to prevent similar vulnerabilities from emerging in time synchronization and system management services.