CVE-2024-47181 in Contiki-NG
Summary
by MITRE • 11/27/2024
Contiki-NG is an open-source, cross-platform operating system for IoT devices. An unaligned memory access can be triggered in the two RPL implementations of the Contiki-NG operating system. The problem can occur when either one of these RPL implementations is enabled and connected to an RPL instance. If an IPv6 packet containing an odd number of padded bytes before the RPL option, it can cause the rpl_ext_header_hbh_update function to read a 16-bit integer from an odd address. The impact of this unaligned read is architecture-dependent, but can potentially cause the system to crash. The problem has not been patched as of release 4.9, but will be included in the next release. One can apply the changes in Contiki-NG pull request #2962 to patch the system or wait for the next release.
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Analysis
by VulDB Data Team • 11/27/2024
The vulnerability identified as CVE-2024-47181 affects Contiki-NG, a widely-used open-source operating system designed specifically for Internet of Things deployments. This embedded operating system provides essential networking capabilities for resource-constrained devices while maintaining compatibility across diverse hardware platforms. The issue stems from improper handling of memory access patterns within the Routing Protocol for Low-Power and Lossy Networks implementations that are integral components of Contiki-NG's networking stack. These RPL implementations are critical for establishing and maintaining network connectivity in IoT environments where power efficiency and reliability are paramount.
The technical flaw manifests as an unaligned memory access condition within the rpl_ext_header_hbh_update function, which processes hop-by-hop options in IPv6 packets. When an IPv6 packet contains an odd number of padding bytes preceding the RPL option, the system attempts to read a 16-bit integer from an address that is not properly aligned to a 16-bit boundary. This type of memory access violation occurs because the processor architecture requires aligned access for certain data types, particularly on ARM and other RISC-based processors commonly found in IoT devices. The vulnerability represents a classic case of improper memory handling that can be classified under CWE-123 as improper handling of memory access violations.
The operational impact of this vulnerability extends beyond simple system instability, potentially leading to complete system crashes that can compromise the availability of IoT devices in critical deployments. In environments where continuous operation is essential, such as industrial monitoring systems, smart grid infrastructure, or emergency response networks, a crash caused by this vulnerability could result in service interruptions that may have serious consequences. The architecture-dependent nature of the impact means that devices running on different processor families may exhibit varying behaviors, with some systems experiencing immediate crashes while others might demonstrate more subtle performance degradation. This vulnerability aligns with ATT&CK technique T1499.001, which involves network denial of service attacks that can be achieved through memory corruption vulnerabilities.
Security researchers have identified that this issue affects Contiki-NG release 4.9 and earlier versions, with the fix planned for inclusion in the subsequent release. The recommended mitigation strategy involves applying the changes from Contiki-NG pull request #2962, which provides a targeted patch addressing the specific memory alignment issue in the RPL option processing code. Organizations deploying Contiki-NG-based IoT solutions should prioritize updating their systems to prevent potential exploitation, particularly in environments where adversaries might attempt to leverage this vulnerability for disruption. The vulnerability highlights the importance of proper memory management in embedded systems and demonstrates how seemingly minor implementation details can have significant security implications in resource-constrained IoT deployments. The fix addresses the root cause by ensuring that all 16-bit integer reads occur from properly aligned memory addresses, thereby preventing the processor from encountering alignment faults during packet processing operations.