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  • Oct 26, 2026, 2:40 PM

    There was a steal my bitcoin challenge which offered some bitcoin if the PHP instance could be compromised. It was won after 19.28 hours.

    The solution exploit has been posted, which I've confirmed to work.

    From the exploit:

    The offsets and multipart shapes are calibrated for the challenge's observed Alpine PHP 8.4.26 layout.

    Which was presumably observable from the live server. The exploit targets a combination of stock nginx:1.27-alpine and php:8.4.26-fpm-alpine3.23 docker images that talk to each other via the php development CLI server. Note that this is probably not representative of what you might see in the real world, and more like what you might see in a CTF.

    However, what you might see in the real world with a real product might be even more terrifying, such as current products that are built on FreeBSD versions too old to even support ASLR.

    two attempts at running stealmybitcoin_poc.py
first attempt failed, second succeeded.
    modified poc to print response body output:
[health] PHP 8.4.26 confirmed
[heap] strict Zend base 0x7668e5800000
[code] strict zval_ptr_dtor 0x62de7ad12930
b'<br />\n<b>Fatal error</b>:  Allowed memory size of 134217728 bytes exhausted (tried to allocate 131072 bytes) in <b>Unknown</b> on line <b>0</b><br />\n25dabf52dede9200\nuid=0(root) gid=0(root) groups=0(root),0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),11(floppy),20(dialout),26(tape),27(video)\n0ec066e8b91457c7c19b5612f3e2ded7f117df08f402693669c1ffc2cfc24942  /usr/local/bin/print-flag\nLOCAL_DUMMY_WIF_NEVER_USE\n'
{"stage": "final", "nonce": "25dabf52dede9200", "execution_proof_verified": true, "response_path": "poc-run-20261026T142543686306Z/final.response.http"}
    💬 1🔄 28⭐ 4

Replies

  • Oct 29, 2026, 6:50 AM

    @wdormann only two hours if you take away the time the host was not configured to properly use PHP. Also with not-so-default setup by using php binary to serve the host.

    💬 0🔄 0⭐ 0