CVE-2018-6948 in CCN-lite
Summary
by MITRE
In CCN-lite 2, the function ccnl_prefix_to_str_detailed can cause a buffer overflow, when writing a prefix to the buffer buf. The maximal size of the prefix is CCNL_MAX_PREFIX_SIZE; the buffer has the size CCNL_MAX_PREFIX_SIZE. However, when NFN is enabled, additional characters are written to the buffer (e.g., the "NFN" and "R2C" tags). Therefore, sending an NFN-R2C packet with a prefix of size CCNL_MAX_PREFIX_SIZE can cause an overflow of buf inside ccnl_prefix_to_str_detailed.
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Analysis
by VulDB Data Team • 02/06/2023
The vulnerability identified as CVE-2018-6948 affects CCN-lite version 2, a content centric networking implementation that operates within the CCN protocol framework. This issue resides in the ccnl_prefix_to_str_detailed function which serves as a critical component for serializing prefix information into string representations. The flaw manifests when processing NFN (Named Function Network) packets that incorporate R2C (Resolve to Content) functionality, creating a scenario where buffer boundaries are exceeded during prefix serialization operations. The vulnerability represents a classic buffer overflow condition that can be exploited to compromise system integrity and potentially execute arbitrary code within the context of the affected application.
The technical root cause of this vulnerability stems from a mismatch between the expected buffer size and the actual data requirements when NFN functionality is enabled. The system allocates a buffer of size CCNL_MAX_PREFIX_SIZE to accommodate prefix information, yet the implementation does not account for additional overhead required when processing NFN-R2C packets. Specifically, the function writes supplementary characters including "NFN" and "R2C" tags directly into the same buffer space, effectively reducing the available capacity for the actual prefix data. When an attacker crafts a malicious NFN-R2C packet containing a prefix of exactly CCNL_MAX_PREFIX_SIZE bytes, the function attempts to write beyond the allocated buffer boundaries, causing memory corruption that can be leveraged for exploitation.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates opportunities for remote code execution and system compromise within environments utilizing CCN-lite with NFN support. Attackers can potentially construct malicious packets that trigger the buffer overflow condition, leading to denial of service scenarios or more severe consequences including privilege escalation and unauthorized access to network resources. The vulnerability affects systems that process content centric networking traffic and specifically those implementing the Named Function Network extension for distributed computing scenarios. Given the nature of content centric networking protocols, this flaw could impact a wide range of applications including content delivery networks, distributed computing frameworks, and IoT communication systems that rely on CCN-lite implementations.
Mitigation strategies for this vulnerability should focus on implementing proper bounds checking and buffer size validation within the ccnl_prefix_to_str_detailed function. The most effective approach involves modifying the buffer allocation logic to account for the additional overhead required when NFN functionality is enabled, ensuring that sufficient space exists for both the prefix data and the supplementary tags. Additionally, input validation should be strengthened to prevent oversized prefix data from being processed, and the function should include explicit bounds checking before writing to the buffer. Organizations should also consider implementing network segmentation and access controls to limit exposure to potentially malicious traffic, while monitoring for anomalous packet patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and could be mapped to ATT&CK technique T1059 for remote code execution through network protocols, emphasizing the need for comprehensive defensive measures.