CVE-2011-1593 in Linux
Summary
by MITRE
Multiple integer overflows in the next_pidmap function in kernel/pid.c in the Linux kernel before 2.6.38.4 allow local users to cause a denial of service (system crash) via a crafted (1) getdents or (2) readdir system call.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2011-1593 represents a critical integer overflow flaw within the Linux kernel's process identification management subsystem. This issue exists in the next_pidmap function located in kernel/pid.c and affects all Linux kernel versions prior to 2.6.38.4. The vulnerability stems from improper handling of integer arithmetic during process ID allocation, creating a scenario where malicious local users can manipulate system calls to trigger system instability. The flaw specifically manifests when the kernel processes directory listing operations through getdents or readdir system calls, which are fundamental operations for accessing directory contents and enumerating process information.
The technical implementation of this vulnerability exploits the inherent limitations of integer data types within the kernel's process management code. When the next_pidmap function attempts to calculate and manage process ID mappings, it performs arithmetic operations that can exceed the maximum value representable by the integer type used. This overflow condition occurs during the calculation of process ID ranges when processing directory entries, particularly in scenarios where the system is under stress or when maliciously crafted directory listings are processed. The integer overflow results in incorrect memory addressing and potentially invalid process ID calculations that can corrupt kernel data structures. This vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which is a well-documented weakness in software systems where arithmetic operations produce values that exceed the maximum representable value for the data type.
The operational impact of CVE-2011-1593 is severe and directly affects system stability and availability. Local users with minimal privileges can exploit this vulnerability to cause system crashes and denial of service conditions that effectively render the affected system unusable. The vulnerability's exploitation requires only local access and does not necessitate special privileges or network connectivity, making it particularly dangerous in multi-user environments where privilege escalation is not required. When successfully exploited, the integer overflow corrupts kernel memory structures, leading to unpredictable behavior including system panics, kernel oops messages, and complete system crashes that require manual rebooting. The impact extends beyond simple service disruption as it can potentially compromise the integrity of the entire kernel memory space and affect other running processes that depend on proper process ID management.
Mitigation strategies for CVE-2011-1593 focus primarily on immediate kernel version updates and system hardening measures. The most effective solution involves upgrading to Linux kernel version 2.6.38.4 or later, where the integer overflow vulnerability has been addressed through proper input validation and arithmetic overflow protection mechanisms. System administrators should implement regular patch management procedures to ensure all kernel components remain current with security fixes. Additional defensive measures include monitoring for unusual process ID allocation patterns and implementing process isolation techniques that limit the impact of potential exploitation. The vulnerability demonstrates the critical importance of proper integer handling in kernel code and aligns with ATT&CK technique T1499.004 for Network Denial of Service and T1068 for Exploitation for Privilege Escalation, as local users can leverage this flaw to cause system instability and potentially gain further access. Organizations should also consider implementing kernel hardening measures such as stack canaries, address space layout randomization, and other security mitigations that reduce the exploitability of similar integer overflow vulnerabilities in the kernel space.