T1055.014: VDSO Hijacking

Adversaries may inject malicious code into processes via VDSO hijacking in order to evade process-based defenses as well as possibly elevate privileges. Virtual dynamic shared object (vdso) hijacking is a method of executing arbitrary code in the address space of a separate live process.

VDSO hijacking involves redirecting calls to dynamically linked shared libraries. Memory protections may prevent writing executable code to a process via Ptrace System Calls. However, an adversary may hijack the syscall interface code stubs mapped into a process from the vdso shared object to execute syscalls to open and map a malicious shared object. This code can then be invoked by redirecting the execution flow of the process via patched memory address references stored in a process' global offset table (which store absolute addresses of mapped library functions).

Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via VDSO hijacking may also evade detection from security products since the execution is masked under a legitimate process.

Detection

IDDS0009Data source and componentProcess: OS API ExecutionDescription

Monitor for malicious usage of system calls, such as ptrace and mmap, that can be used to attach to, manipulate memory, then redirect a processes' execution path. Monitoring for Linux specific calls such as the ptrace system call should not generate large amounts of data due to their specialized nature, and can be a very effective method to detect some of the common process injection methods.

IDDS0011Data source and componentModule: Module LoadDescription

Monitor library load events, especially unusual creation of these binary files followed by loading into processes. Look for libraries that are not recognized or not normally loaded into a process.

Mitigation

IDM1040NameBehavior Prevention on EndpointDescription

Some endpoint security solutions can be configured to block some types of process injection based on common sequences of behavior that occur during the injection process.