CVE-2017-10987 in FreeRADIUS
Summary
by MITRE
An FR-GV-304 issue in FreeRADIUS 3.x before 3.0.15 allows "DHCP - Buffer over-read in fr_dhcp_decode_suboptions()" and a denial of service.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability CVE-2017-10987 represents a critical buffer over-read flaw in the FreeRADIUS server software that specifically affects versions 3.x prior to 3.0.15. This issue manifests within the DHCP functionality of the radius server where the fr_dhcp_decode_suboptions() function fails to properly validate input data during DHCP suboption decoding processes. The flaw occurs when the DHCP server receives malformed or specially crafted DHCP packets that contain oversized or improperly formatted suboptions, leading to memory access violations beyond the allocated buffer boundaries.
The technical implementation of this vulnerability stems from inadequate bounds checking within the DHCP decoding routine that processes suboption data structures. When the FreeRADIUS server encounters DHCP packets with maliciously constructed suboptions, the fr_dhcp_decode_suboptions() function attempts to read memory locations that extend beyond the intended buffer limits. This over-read condition can result in unpredictable behavior including application crashes, memory corruption, or in some cases, potential information disclosure through reading adjacent memory segments. The vulnerability is classified as a buffer over-read condition under CWE-125, which specifically addresses out-of-bounds read vulnerabilities that can lead to denial of service or information leakage.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it can be exploited by remote attackers to disrupt network authentication services that rely on FreeRADIUS for DHCP functionality. Organizations utilizing FreeRADIUS servers in network infrastructure environments where DHCP services are enabled become vulnerable to this attack vector, potentially compromising network access control and authentication mechanisms. The vulnerability affects systems where FreeRADIUS operates as a DHCP server or processes DHCP packets as part of its authentication workflow, making it particularly dangerous in enterprise environments where network access control is critical.
This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service and represents a classic example of how protocol parsing flaws can be exploited to create service disruption. The attack requires minimal privileges and can be executed remotely, making it particularly dangerous in networked environments where DHCP services are exposed to untrusted networks. Organizations should prioritize patching this vulnerability as it represents a significant risk to network availability and authentication infrastructure. The recommended mitigation strategy involves upgrading to FreeRADIUS version 3.0.15 or later, which includes proper bounds checking and input validation for DHCP suboption decoding processes. Additionally, network segmentation and access controls should be implemented to limit exposure of FreeRADIUS servers to untrusted networks, while monitoring systems should be configured to detect anomalous DHCP traffic patterns that might indicate exploitation attempts.