CVE-2023-49062 in Katran
Summary
by MITRE • 11/28/2023
Katran could disclose non-initialized kernel memory as part of an IP header. The issue was present for IPv4 encapsulation and ICMP (v4) Too Big packet generation. After a bpf_xdp_adjust_head call, Katran code didn’t initialize the Identification field for the IPv4 header, resulting in writing content of kernel memory in that field of IP header. The issue affected all Katran versions prior to commit 6a03106ac1eab39d0303662963589ecb2374c97f
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Analysis
by VulDB Data Team • 12/17/2023
The vulnerability identified as CVE-2023-49062 represents a critical information disclosure flaw within Katran, a high-performance load balancing solution developed by Facebook for Linux kernel environments. This issue specifically targets the handling of IPv4 packet processing within the kernel space, where uninitialized memory contents are inadvertently exposed through network packet headers. The vulnerability manifests during the generation of ICMPv4 "Too Big" packets and IPv4 encapsulation operations, making it particularly dangerous in network infrastructure contexts where such packets are frequently processed.
The technical root cause of this vulnerability stems from improper memory initialization practices within the Katran codebase, specifically following the execution of bpf_xdp_adjust_head function calls. When processing network packets, the system performs memory manipulation operations that alter packet headers, but fails to properly initialize the Identification field within the IPv4 header structure. This field, which should contain a unique identifier for tracking fragmented packets, instead contains arbitrary kernel memory contents that were never explicitly set to zero or a valid value. The CWE-119 weakness classification applies here as this represents an improper access to uninitialized memory, while the vulnerability directly maps to CWE-248 as it involves exposure of uninitialized memory contents.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked kernel memory contents could potentially contain sensitive data such as cryptographic keys, session tokens, or other confidential information stored in kernel memory regions. Attackers could exploit this weakness by crafting specific network traffic patterns that trigger the vulnerable code path, particularly when ICMPv4 "Too Big" messages are generated due to packet size limitations. The vulnerability affects all versions of Katran prior to commit 6a03106ac1eab39d0303662963589ecb2374c97f, making it a persistent threat across multiple releases. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1005 as it involves data from local system collection, and T1041 as it enables information discovery through network traffic analysis.
The mitigation strategy for CVE-2023-49062 requires immediate deployment of the patched version containing commit 6a03106ac1eab39d0303662963589ecb2374c97f, which properly initializes the IPv4 Identification field after bpf_xdp_adjust_head operations. Organizations should also implement network monitoring to detect unusual ICMP packet patterns that might indicate exploitation attempts, while maintaining regular security updates for all kernel-based network components. The fix ensures that all IPv4 headers generated by Katran maintain proper initialization of critical fields, preventing unauthorized access to kernel memory contents and eliminating the information disclosure risk.