CVE-2013-4391 in systemd
Summary
by MITRE
Integer overflow in the valid_user_field function in journal/journald-native.c in systemd allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a large journal data field, which triggers a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 01/09/2022
The vulnerability identified as CVE-2013-4391 represents a critical integer overflow condition within systemd's journal daemon component, specifically affecting the valid_user_field function in the journal/journald-native.c source file. This flaw exists in the handling of journal data fields where the system fails to properly validate input sizes before processing them, creating a scenario where maliciously crafted data can trigger unexpected behavior. The vulnerability manifests when remote attackers submit journal entries containing excessively large data fields, which then causes the system to miscalculate memory allocation sizes during processing.
The technical implementation of this vulnerability stems from inadequate input validation and arithmetic overflow handling within the systemd journal daemon's native protocol processing layer. When the valid_user_field function processes incoming journal data, it performs integer arithmetic operations without proper bounds checking to determine buffer allocation sizes. This oversight creates a condition where a carefully crafted large data field can cause integer overflow, resulting in insufficient memory allocation that subsequently leads to heap-based buffer overflow conditions. The vulnerability operates at the intersection of memory safety and protocol parsing, making it particularly dangerous as it can be triggered through legitimate network communication channels.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution, making it a significant threat to system integrity and availability. When exploited, the heap-based buffer overflow can cause the journal daemon to crash, leading to system instability and potential service disruption. More critically, the memory corruption resulting from the buffer overflow may allow attackers to manipulate program execution flow, potentially enabling arbitrary code execution with the privileges of the journal daemon process. This represents a serious escalation from basic denial of service to full system compromise, particularly in environments where systemd serves as a core system component.
Mitigation strategies for CVE-2013-4391 should focus on immediate patching of affected systemd versions, implementing input validation controls, and monitoring for suspicious journal data patterns. System administrators should prioritize updating to patched versions of systemd where available, as the vulnerability affects multiple versions of the service management framework. Network-level controls including firewall rules to restrict journal daemon communication and monitoring for unusual data field sizes can provide additional defense-in-depth measures. The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and maps to ATT&CK technique T1059.008 for execution through system services, highlighting the need for comprehensive security controls across multiple attack surface areas. Organizations should also implement automated patch management processes to ensure timely remediation of similar vulnerabilities in system components that handle external data input processing.