CVE-2011-1770 in Linux
Summary
by MITRE
Integer underflow in the dccp_parse_options function (net/dccp/options.c) in the Linux kernel before 2.6.33.14 allows remote attackers to cause a denial of service via a Datagram Congestion Control Protocol (DCCP) packet with an invalid feature options length, which triggers a buffer over-read.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2011-1770 represents a critical integer underflow condition within the Linux kernel's Datagram Congestion Control Protocol implementation. This flaw exists in the dccp_parse_options function located in net/dccp/options.c and affects Linux kernel versions prior to 2.6.33.14. The vulnerability stems from improper validation of feature options length parameters within DCCP packets, creating a scenario where maliciously crafted packets can trigger unexpected behavior in the kernel's network processing subsystem.
The technical implementation of this vulnerability involves an integer underflow condition that occurs when processing DCCP packet options. When a remote attacker sends a DCCP packet containing an invalid feature options length, the kernel's dccp_parse_options function fails to properly validate the input parameters. This validation failure results in a negative integer value being used as a buffer index or length parameter, causing the kernel to attempt to read from memory locations that are outside the intended buffer boundaries. The underflow condition specifically manifests when the calculated buffer offset becomes negative due to improper arithmetic operations on the feature options length field.
The operational impact of this vulnerability extends to potential denial of service conditions that can severely impact system availability. When exploited, the integer underflow causes the kernel to perform invalid memory operations that can result in system crashes, kernel panics, or complete system hangs. These conditions can be triggered by sending a single malicious DCCP packet to a vulnerable system, making the attack vector particularly dangerous for network services that rely on DCCP protocol support. The vulnerability affects systems running Linux kernels where DCCP functionality is enabled, potentially impacting servers, routers, and network infrastructure devices that utilize this congestion control protocol.
This vulnerability maps directly to CWE-191, which describes Integer Underflow (Wrap or Wraparound) in software security contexts. The flaw demonstrates how improper input validation and arithmetic operations can lead to memory safety issues that compromise system stability. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1499.004, which involves network denial of service attacks through protocol manipulation. The attack requires minimal sophistication and can be automated, making it particularly attractive to threat actors seeking to disrupt network services. The vulnerability also corresponds to ATT&CK technique T1595.001, which involves reconnaissance through protocol analysis, as attackers would need to identify vulnerable systems and craft appropriate malicious packets.
Mitigation strategies for CVE-2011-1770 primarily focus on kernel version updates and network-level protections. The most effective remediation involves upgrading to Linux kernel version 2.6.33.14 or later, where the integer underflow has been properly addressed through enhanced input validation and arithmetic boundary checks. Network administrators should implement firewall rules to filter DCCP traffic when the protocol is not required for legitimate services, as this reduces the attack surface. Additionally, monitoring systems for unusual network traffic patterns or kernel panic events can help detect exploitation attempts. Organizations should also consider implementing intrusion detection systems that can identify malformed DCCP packets and trigger alerts for further investigation. The vulnerability highlights the importance of proper integer arithmetic validation in kernel space code and serves as a reminder of the critical need for thorough input validation in network protocol implementations.