Php 5.5.9 Exploit Direct

The logs went silent.

First, the reconnaissance. A simple GET /info.php revealed the banner: PHP/5.5.9-1ubuntu4.29 . The attacker had smiled. php 5.5.9 exploit

“That’s how they’re persisting,” she whispered. The logs went silent

But the magic wasn't in the crash. It was in the resurrection. The attacker had smiled

Then, the trigger. A crafted HTTP request with a malicious User-Agent header, longer than a novella, containing a specific sequence of null bytes and heap spray data. The get_headers() function, when fed a URL with a fragment identifier longer than 1024 bytes, would try to free a memory pointer that was already freed. A classic double-free.

?> She ran it. The PHP-FPM child process crashed, then respawned. But in the microsecond between free and respawn, she injected a tracer. The memory register showed a dangling pointer pointing directly to the system() function in libc.