CVE-2016-4577 in NGFW Module
Summary
by MITRE
Buffer overflow in the Smart DNS functionity in the Huawei NGFW Module and Secospace USG6300, USG6500, USG6600, and USG9500 firewalls with software before V500R001C20SPC100 allows remote attackers to cause a denial of service or execute arbitrary code via a crafted packet, related to "illegitimate parameters."
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Analysis
by VulDB Data Team • 08/22/2022
The vulnerability identified as CVE-2016-4577 represents a critical buffer overflow flaw within the Smart DNS functionality of Huawei Next Generation Firewall modules and Secospace USG series devices. This security weakness affects multiple firewall models including the USG6300, USG6500, USG6600, and USG9500 platforms operating with software versions prior to V500R001C20SPC100. The vulnerability stems from inadequate input validation within the Smart DNS processing mechanism, which fails to properly handle malformed or oversized parameter inputs. The flaw specifically manifests when the system encounters illegitimate parameters during DNS request processing, creating a condition where attacker-controlled data can overwrite adjacent memory locations beyond the allocated buffer boundaries.
The technical implementation of this vulnerability involves the exploitation of improper bounds checking within the DNS handling routines of Huawei's firewall firmware. When a remote attacker crafts a malicious packet containing oversized or malformed DNS parameters, the system's Smart DNS function fails to validate the input length before copying it into a fixed-size buffer. This classic buffer overflow condition allows an attacker to overwrite critical memory locations including return addresses, function pointers, or other control data structures. The vulnerability's remote exploitability means that attackers do not require physical access or local network credentials to initiate the attack, making it particularly dangerous in networked environments where firewalls serve as critical security gateways.
The operational impact of CVE-2016-4577 extends beyond simple denial of service conditions to encompass potential remote code execution capabilities. Successful exploitation can result in complete system compromise, allowing attackers to execute arbitrary code with the privileges of the firewall process, typically running with elevated system permissions. The denial of service aspect can render the firewall inoperable, creating security gaps in network protection while the code execution capability enables persistent backdoor access, data exfiltration, or further network reconnaissance activities. Given that these firewalls are deployed in enterprise and critical infrastructure environments, the potential for widespread disruption and security breaches is significant, particularly when considering that the vulnerability affects multiple generations of Huawei's security appliances.
Organizations should prioritize immediate remediation through official Huawei firmware updates addressing the V500R001C20SPC100 software version or higher, which contain the necessary input validation patches. Network segmentation and access controls should be implemented to limit exposure of affected devices to untrusted networks, while monitoring systems should be configured to detect anomalous DNS traffic patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to ATT&CK technique T1059.007 for remote code execution through network services. Security teams should also consider implementing intrusion detection systems with signatures specifically targeting the malformed DNS packet patterns associated with this vulnerability to detect and prevent exploitation attempts in real-time environments.