CVE-2011-1493 in Linux
Summary
by MITRE
Array index error in the rose_parse_national function in net/rose/rose_subr.c in the Linux kernel before 2.6.39 allows remote attackers to cause a denial of service (heap memory corruption) or possibly have unspecified other impact by composing FAC_NATIONAL_DIGIS data that specifies a large number of digipeaters, and then sending this data to a ROSE socket.
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability identified as CVE-2011-1493 represents a critical array index error within the Linux kernel's ROSE (Remote Operations Signaling Environment) subsystem. This flaw exists in the rose_parse_national function located in net/rose/rose_subr.c and affects kernel versions prior to 2.6.39. The ROSE protocol is part of the Linux kernel's implementation of the X.25 packet-switched network protocol suite, specifically designed for amateur radio applications and other specialized communication networks. The vulnerability manifests when processing FAC_NATIONAL_DIGIS data structures that contain an excessive number of digipeater specifications, creating a scenario where memory corruption can occur through improper array bounds checking.
The technical exploitation of this vulnerability occurs when remote attackers craft malicious FAC_NATIONAL_DIGIS data packets containing a large number of digipeaters that exceed the intended array size limits. The rose_parse_national function fails to properly validate the number of digipeaters specified in the incoming data, leading to an array index error that results in heap memory corruption. This type of vulnerability falls under CWE-129, which describes improper validation of array index values, and represents a classic example of an out-of-bounds write condition. The flaw allows attackers to manipulate memory layout and potentially execute arbitrary code or cause system instability through a carefully constructed denial of service attack.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more severe security consequences. When exploited, the heap memory corruption can cause the kernel to crash or behave unpredictably, leading to complete system denial of service. In some scenarios, the memory corruption might be exploitable for privilege escalation or arbitrary code execution depending on the specific memory layout and system configuration. The vulnerability affects systems utilizing the ROSE protocol implementation in the Linux kernel, which includes specialized communication equipment and amateur radio networks that rely on kernel-level packet processing. The attack vector requires network access to a system running the vulnerable kernel version and listening on ROSE sockets, making it particularly concerning for network infrastructure and communication systems.
Mitigation strategies for CVE-2011-1493 primarily involve upgrading to Linux kernel versions 2.6.39 or later where the vulnerability has been addressed through proper bounds checking in the rose_parse_national function. System administrators should implement network segmentation and access controls to limit exposure of ROSE protocol endpoints to untrusted networks. The fix typically involves adding proper validation of digipeater count parameters before array indexing operations, ensuring that the number of specified digipeaters does not exceed predefined safe limits. Organizations should also consider implementing network monitoring to detect unusual FAC_NATIONAL_DIGIS data patterns and establish incident response procedures for potential exploitation attempts. This vulnerability demonstrates the importance of input validation in kernel space operations and aligns with ATT&CK technique T1068, which covers the exploitation of system vulnerabilities for privilege escalation and denial of service attacks.