Fuzzing has become one of the most effective and widely used techniques for discovering bugs and vulnerabilities, particularly in large-scale and complex programs like operating system kernels. A notable example is the kernel fuzzer syzkaller, which has identified over 6,800 bugs in the Linux kernel, with more than 5,500 already fixed. A crucial reason behind the success of the syzkaller is its collection of syscall descriptions, which are typically provided by human experts. Although some methods exist for automatically generating these syscall descriptions for device drivers, they often fall short when dealing with complex user inputs. These existing methods either lack precision or have a limited analysis scope, resulting in incomplete syscall descriptions.

Public IP addresses can expose devices and services to risks such as port scanning and subsequent cyberattacks. Therefore, firewalls are extensively deployed and play a critical role in enforcing security policies and preventing unauthorized access. However, vulnerabilities can allow firewalls to be by-passed, effectively nullifying the protection. In this paper, we present the first comprehensive study of a previously understudied attack surface: firewall misconfigurations that inadvertently expose protected services to the public Internet. Specifically, we demonstrate flawed firewall rules that allow inbound connections from special source ports to bypass the firewall, and explore the prevalence and security implications thereof. To this end, we scan the IPv4 space for 15 commonly high-risk TCP and UDP services from two special source ports. Our measurement reveals the widespread existence of such misconfigurations and identified over 2,000,000 otherwise unreachable services spread over 15,837 autonomous systems, expanding the “observable Internet” for various protocols by up to 12.60%. More importantly, the affected services generally exhibit higher security risks than the publicly accessible ones, like outdated software versions and weak configurations. Despite the severity of this vulnerability, our honeypot experiment provides little evidence of active exploitation in the wild. Our findings offer insights for better security posture and network administration, helping researchers and organizations anticipate and mitigate potential cyber threats emanating from the Internet.

Home wireless mesh networks (WMNs) are increasingly gaining popularity for their superior extensibility and signal coverage compared to traditional single-AP wireless networks. In particular, there is a single gateway node and multiple extender nodes that cooperate to provide wireless coverage. We observe that there is no comprehensive research conducted on the security aspects of the control plane of such networks. For example, this decentralized architecture enables each extender node to independently authenticate wireless clients by synchronizing access control policies from the gateway node. However, this synchronization unexpectedly opens an attack surface which has not been scrutinized.