BusyBox

Pivoting in Legacy Hell: Navigating MIPS Servers, BusyBox, and 2014 Kernels During Internal Network Assessments

The article details a complete methodology for pivoting from an initial SSH compromise on an old Debian MIPS server to reach a hidden web admin panel inside a segmented network. It covers environment enumeration with commands like uname -a and ip route, followed by setting up a Chisel-based SOCKS5 proxy when standard SSH dynamic forwarding is disabled by server configuration. Scanning proceeds via proxychains with nmap using -sT, -Pn, and -n flags or by deploying static MIPS binaries directly on the host. Traffic is then routed through Burp Suite chained to the SOCKS proxy for password guessing against the web interface. The piece emphasizes practical constraints such as BusyBox limitations, kernel version incompatibilities with modern binaries, and the need for careful subnet identification. Readers are directed to replicate the full chain in the Forgotten Server task from the free White Hacker Profession course.

Dirty COW CVE-2016-5195: How a 2016 Linux Kernel Race Condition Still Enables Privilege Escalation in Embedded Systems

The 2016 Linux kernel vulnerability CVE-2016-5195, known as Dirty COW, allowed local users to bypass copy-on-write protections and modify read-only memory mappings through a race condition involving writes to /proc/self/mem and madvise calls. Although patched in supported distributions years ago, the flaw persists in older kernels running on routers, cameras, and industrial controllers that receive infrequent firmware updates. Public exploits often target /etc/passwd or SUID binaries for root access, but success depends heavily on the presence of login mechanisms, BusyBox applets, and suitable binaries in the target environment. When standard targets are absent, attackers may pivot to overwriting vDSO functions in process memory to inject code executed by higher-privileged processes. The article explains why ready-made PoCs frequently fail on minimal BusyBox-based systems and outlines the checks required for architecture, ABI, vDSO symbols, and payload compatibility. It also references the practical exercise Strange And Dirty on the free White Hacker course for hands-on adaptation of the exploit chain.