CVE-2016-8773 in S5300
Summary
by MITRE
Huawei S5300 with software V200R003C00, V200R007C00, V200R008C00, V200R009C00; S5700 with software V200R001C00, V200R002C00, V200R003C00, V200R005C00, V200R005C03, V200R007C00, V200R008C00, V200R009C00; S6300 with software V200R003C00, V200R005C00, V200R008C00, V200R009C00; S6700 with software V200R001C00, V200R001C01, V200R002C00, V200R003C00, V200R005C00, V200R008C00, V200R009C00; S7700 with software V200R007C00, V200R008C00, V200R009C00; S9300 with software V200R007C00, V200R008C00, V200R009C00; S9700 with software V200R007C00, V200R008C00, V200R009C00; and S12700 with software V200R007C00, V200R007C01, V200R008C00, V200R009C00 allow the attacker to cause a denial of service condition by sending malformed MPLS packets.
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Analysis
by VulDB Data Team • 11/24/2022
The vulnerability identified as CVE-2016-8773 represents a critical denial of service weakness affecting multiple Huawei networking devices including the S5300, S5700, S6300, S6700, S7700, S9300, S9700, and S12700 series switches. This flaw specifically targets the MPLS packet processing functionality within these network appliances, creating a condition where maliciously crafted packets can trigger system instability. The affected software versions span across several major releases including V200R003C00, V200R007C00, V200R008C00, and V200R009C00, indicating a widespread issue that impacts a significant portion of Huawei's enterprise networking portfolio. The vulnerability falls under CWE-129, which addresses improper validation of array index values, and can be classified as a buffer overflow condition when processing malformed MPLS packets. This weakness creates an operational risk where network availability is compromised, potentially disrupting critical business operations and network services.
The technical implementation of this vulnerability occurs when the affected Huawei switches receive specially crafted MPLS packets that contain malformed data structures or invalid packet headers. The device's MPLS processing engine fails to properly validate incoming packet formats, allowing attackers to exploit this validation gap through carefully constructed packets that exceed expected parameter boundaries. When the switch attempts to process these malformed packets, the system enters an unstable state that results in complete service disruption. This behavior aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through malformed packets, and represents a classic example of how protocol implementation flaws can be weaponized to achieve system compromise. The vulnerability demonstrates poor input validation practices in the network switch's packet processing pipeline, where insufficient bounds checking allows malicious data to cause unexpected behavior in the routing engine.
The operational impact of CVE-2016-8773 extends beyond simple service interruption to encompass potential business continuity risks for organizations relying on Huawei networking infrastructure. Network administrators face the challenge of maintaining service availability while implementing mitigations, as the vulnerability can be exploited remotely without requiring authentication credentials. The affected devices represent core components of enterprise network infrastructure, making the potential for widespread disruption significant. Organizations utilizing these switches may experience cascading failures as network segments become isolated due to the denial of service condition. The vulnerability's exploitation can lead to extended downtime for network services, particularly in environments where MPLS traffic is prevalent, such as service provider networks or large enterprise environments with complex routing requirements. This condition directly impacts the availability component of the CIA triad and can result in financial losses due to network downtime and potential service level agreement violations.
Mitigation strategies for CVE-2016-8773 should prioritize immediate firmware updates from Huawei to address the underlying implementation flaw in MPLS packet processing. Network administrators should implement ingress filtering and packet validation mechanisms at network boundaries to prevent malformed MPLS packets from reaching vulnerable devices. The implementation of access control lists and traffic filtering rules can help reduce the attack surface by limiting MPLS traffic to authorized network segments. Additionally, monitoring systems should be enhanced to detect unusual packet patterns that may indicate exploitation attempts, enabling rapid response to potential attacks. Organizations should also consider implementing network segmentation strategies to isolate vulnerable switches from critical network services, reducing the potential impact of successful exploitation. The vulnerability highlights the importance of regular security assessments and firmware maintenance programs, as the flaw exists in multiple software versions across different device families, indicating a systemic issue that requires comprehensive remediation across the entire network infrastructure.