Zend Engine V3.4.0 - Exploit

| Tool | Purpose | |------|---------| | gdb + php-dbg | Step through zend_execute.c | | valgrind | Detect Zend memory errors | | php -m | List dangerous extensions (e.g., FFI, dl) | | vld (Vulkan Logic Dumper) | Dump Zend opcodes | | phpphp (PHP fuzzer) | Crash Zend VM via malformed AST |

$arr = [];
$arr[] = &$arr;
unset($arr);
gc_collect_cycles();
// Some UAF conditions may occur in zend_gc.c

You might think, "Zend Engine v3.4.0 is obsolete." Yet, penetration testers frequently encounter it for three reasons: zend engine v3.4.0 exploit

$size = pow(2, 16);
$keys = [];
for ($i = 0; $i < $size; $i++) 
    $keys["\0" . $i] = 1;
// Causes O(n^2) insertion time due to collision chain