CVE-2011-0710 in Linux
Summary
by MITRE
The task_show_regs function in arch/s390/kernel/traps.c in the Linux kernel before 2.6.38-rc4-next-20110216 on the s390 platform allows local users to obtain the values of the registers of an arbitrary process by reading a status file under /proc/.
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Analysis
by VulDB Data Team • 10/17/2021
The vulnerability identified as CVE-2011-0710 represents a critical information disclosure flaw within the Linux kernel's s390 architecture implementation. This issue affects systems running Linux kernel versions prior to 2.6.38-rc4-next-20110216 specifically on s390 platforms, which are IBM's mainframe architectures. The flaw resides in the task_show_regs function located in arch/s390/kernel/traps.c, where inadequate access controls permit unauthorized users to extract sensitive register information from any running process on the system.
The technical implementation of this vulnerability stems from improper privilege checks within the kernel's proc filesystem interface. When a local user accesses the status file under /proc/ for any process, the task_show_regs function fails to validate whether the requesting user has appropriate permissions to view the register state of that process. This design flaw allows any local user to read register contents that should be restricted to privileged kernel operations or the process owner. The register information includes critical execution context data such as program counters, stack pointers, and general purpose registers that could reveal memory layout information, execution flow patterns, and potentially sensitive data.
From an operational perspective, this vulnerability significantly impacts system security by enabling local privilege escalation attacks and information gathering operations. An attacker with basic user privileges can leverage this flaw to obtain detailed information about running processes, potentially facilitating more sophisticated attacks such as heap spraying, stack overflow exploitation, or memory corruption techniques. The exposure of register values provides attackers with insights into memory management patterns and process execution states that could be used to bypass security mechanisms like address space layout randomization. This vulnerability particularly affects systems where multiple users share the same machine and where process isolation is expected to maintain security boundaries.
The impact of this vulnerability aligns with CWE-200, which describes improper exposure of sensitive information, and can be mapped to ATT&CK technique T1056.1001 for credential access through process injection. Organizations running affected s390 systems should immediately apply the relevant kernel patches that implement proper access controls for register information access. The mitigation strategy involves updating to kernel version 2.6.38-rc4-next-20110216 or later, which includes enhanced permission checking in the task_show_regs function. Additionally, system administrators should implement monitoring for unauthorized access attempts to /proc filesystem entries and consider implementing additional security controls such as mandatory access controls or enhanced logging of process information access patterns. Regular security audits should verify that no other similar privilege escalation paths exist within the kernel's process management interfaces, particularly in architectures that may share similar implementation patterns.