CVE-2014-3683 in rsyslog
Summary
by MITRE
Integer overflow in rsyslog before 7.6.7 and 8.x before 8.4.2 and sysklogd 1.5 and earlier allows remote attackers to cause a denial of service (crash) via a large priority (PRI) value. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-3634.
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Analysis
by VulDB Data Team • 02/21/2022
The vulnerability identified as CVE-2014-3683 represents a critical integer overflow flaw affecting rsyslog versions prior to 7.6.7 and 8.x versions prior to 8.4.2, as well as sysklogd versions 1.5 and earlier. This issue specifically targets the handling of priority values within syslog message processing, creating a pathway for remote attackers to execute denial of service attacks. The vulnerability stems from an incomplete remediation of a previous flaw, CVE-2014-3634, which demonstrates the complexity of addressing integer overflow conditions in system logging components. The flaw manifests when the system processes a large priority value that exceeds the maximum representable integer, leading to unexpected behavior in the application's memory management and processing logic.
The technical implementation of this vulnerability involves the manipulation of the priority field within syslog messages, which traditionally consists of a single integer value representing the facility and severity levels. When an attacker sends a syslog message containing an excessively large priority value, the system's integer handling routines overflow beyond their allocated memory boundaries. This overflow condition typically occurs in the parsing and validation stages of syslog message processing where the system attempts to convert the priority string representation into an integer format. The incomplete fix for CVE-2014-3634 left certain edge cases unaddressed, particularly when dealing with boundary conditions in integer arithmetic operations. This oversight creates a scenario where the system's internal state becomes corrupted, leading to application crashes and system instability.
The operational impact of CVE-2014-3683 extends beyond simple service disruption to potentially compromise system availability and integrity within network infrastructure. Remote attackers can exploit this vulnerability without requiring authentication, making it particularly dangerous in environments where syslog services are exposed to untrusted networks. The denial of service effect manifests as complete system crashes or restarts of the affected logging services, which can result in loss of critical system monitoring data and potential cascading failures in dependent services. Organizations relying on centralized logging systems may experience complete logging outages, leaving them without visibility into system events during the attack window. The vulnerability's exploitation can occur through various network protocols including udp and tcp, making it difficult to defend against through simple network filtering measures.
Mitigation strategies for CVE-2014-3683 require immediate patching of affected rsyslog and sysklogd installations to versions that properly address the integer overflow condition. System administrators should prioritize updating to rsyslog 7.6.7 or later, 8.4.2 or later, or sysklogd 1.5 or later, respectively. Network segmentation and access control measures can provide temporary protection by limiting exposure of syslog services to untrusted networks. Implementing proper input validation and bounds checking within syslog message processing can help prevent exploitation of similar vulnerabilities. Additionally, monitoring systems should be configured to detect unusual patterns in syslog traffic that might indicate exploitation attempts. From a cybersecurity perspective, this vulnerability aligns with attack patterns described in the MITRE ATT&CK framework under the service stop technique, where adversaries target system services to cause availability disruption. The vulnerability also relates to CWE-191, Integer Underflow or Wraparound, which specifically addresses integer arithmetic issues that can lead to buffer overflows and system instability. Organizations should implement comprehensive vulnerability management processes to identify and remediate similar issues in other system components that handle integer arithmetic operations.