Hacker News

points by xx_ns 2 days ago | 0 comments

"No successful PHP2Shell exploits seen so far"... in the wild, specifically in Wiz's honeypot. The vulnerability itself has been successfully exploited, most notably for the "Steal my Bitcoin" challenge [1] as one example.

Dan Guido, of Trail of Bits, claims they have an "universal" exploit [2]. Knowing their track record, I don't currently have a reason to doubt this claim.

[1]: https://stealmybitcoin.com/

[2]: https://news.ycombinator.com/item?id=50226010

EDIT: The HN title has been changed since posting this comment.

[–] paxy 2 days ago

It's funny that when stealmybitcoin.com was posted on HN (https://news.ycombinator.com/item?id=50224916) there were hundreds of top voted comments saying "see no one has been able to steal it, the reported vulnerability was fake, it's all AI marketing" etc.

Since it was successfully exploited there has been zero further discussion, and I bet most people who participated in the original thread aren't even aware.

[–] fwlr 2 days ago

As one of those comments I dispute your characterization of it as the reported vulnerability being fake, very few people were saying that. The main thing being called fake was the narrative that with AI it was trivial to exploit the vulnerability.

It has not escaped me that the successful exploit did in fact just say “codex, exploit this” and got it.

I had assumed the rash of commenters saying “lol I am not revealing my AI’s exploit for a measly 500 bucks” were saying that because their AI attempt failed. Now I know they didn’t even try!

[–] ratscylla 2 days ago

If you follow the threads, it looks like the original post wasn’t exploitable. It looks like it was hacked within an hour of being made exploitable (actually running php).

Would be cool to get an accurate timeline / postmortem from the author of the site.

[–] fwlr 2 days ago

Yes, I followed along at the time. As I recall, the explanation of why the server wasn’t exploitable read exactly like an excerpt from a session with a frontier model explaining why its exploit failed.

[–] vikramkr 2 days ago

I mentioned this a couple times there but the unintended consequences of that challenge are wild. 2 hours after it the server was fixed there was a successful exploit but because it was originally misconfigured a huge number of people walk away thinking the vulnerability was not serious. At the least we now know a good way to convince large swarths of technical folks to not take new vulns seriously! Which seems not good

[–] syshyk 2 days ago

The main kickback was against the hype and it was "so easy for AI" and would take "15 minutes to compromise everything".

Either way, this was not true.

[–] vikramkr 2 days ago

It was true. The author had messed up the server and it was not exploitable. It was hacked within a couple hours of the author fixing it (even with the server being down) but the author had also messed up and not put the actual Bitcoin wallet in it so it took an additional 5 hours for them to fix that. It was a mess but the vulnerability was very real

[–] Tadpole9181 2 days ago

The author didn't even have an accessible PHP server at first. When they actually added one, it got cracked in 2 hours.

[–] jgalt212 2 days ago

yes, but 70% of the world's websites were (and many still are) accessible PHP server(s) that hand not been patched.

[–] milkshakes 2 days ago

also it was under hn load which makes this much harder

[–] NorwegianDude 2 days ago

HN load isn't exactly a high load for a server. The automated traffic was most likely much higher, but not high, as the server used the super slow single threaded php dev http server, so high traffic was not possible, everyone had to wait their turn.

[–] elysianfields 2 days ago

The vulnerabilities kinda rely on having to make quite a number of requests to exploit + can crash the process as I understood, so if many people try to force their way in at once 2h doesnt seems like a long timespan.

[–] r_lee 1 day ago

for the single threaded one it's easier from what I can remember

[–] ForHackernews 2 days ago

Two things can be true:

1) A motivated human eager for $500 and internet cred can exploit a vuln (perhaps using AI tooling to help)

2) The vuln is not easily exploitable at scale by driveby bots.

[–] NitpickLawyer 2 days ago

IIUC, the first setup couldn't be exploited because the site didn't run any php. You kinda need the server to run some php if you're gonna use a php vuln. It got solved ~2h after they added a php-version.php ...

[–] ForHackernews 2 days ago

FTA:

> The failed leaks highlight a broader challenge: building a generalized exploit that works reliably across PHP versions and deployment configurations is difficult. The kit’s B1 layout was calculated for the official php:8.4.26-apache image with a 128 MB memory limit. Other instances like our Roundcube honeypot ran the same PHP version from a different build, with additional extensions and a 64 MB memory limit. These differences can affect heap layout and memory reuse, potentially preventing the leak from working as expected.

It sounds like it's hard to put together a generalized write-once-run-everywhere version of the exploit, so you need a human or an expensive LLM backing each attack and trying to adjust for the particulars of that target's deployment.

[–] 0x457 2 days ago

I was trying to steal those, but when I setup my local version, I things a little different: php-fpm and glibc because I thought this how everyone would run php with nginx. PHP-FPM recycled OOM workers, so there were no corrupted state to exploit and then when I switched to "php -s", glibc with ASLR made it not very practical to exploit.

Changed my lab to use the same alpine + php = tada working exploit.

[–] howunfortunate 2 days ago

To be fair, he hasn't had time to do the write up yet. When he does I fully expect it to hit the front page.

[–] Topfi 2 days ago

The person that succeeded already published [0]. Thread is barely active compared with the amount of engagement the challenges announcement received.

[0] https://news.ycombinator.com/item?id=50237379

[–] cimi_ 2 days ago

More details about stealmybitcoin in LiveOverflow's video: https://www.youtube.com/watch?v=VhNiMWtOutw

This is the winner: https://github.com/KillaBoi/StealMyBitcoin-PoC

The challenge website was not exploitable at launch because it wasn't actually running PHP; it got cracked in two hours aftewards

In the video, LiveOverflow shows his exploit that reliably gets RCE from two requests.

[–] rudedogg 2 days ago

> because it wasn't actually running PHP

Yea and no, I mean it was an even worse setup than typical, probably because the person setting it up didn’t have php experience or used an LLM that misinterpreted “route requests from nginx to php” or something too literally and set up a hacky solution.

But my impression isn’t that they set it up in some cheeky way to avoid exploits, it looks like they just asked for nginx to be in front.

And is “hacked in two hours” fair if they had to make it easy for people because their noob setup ended up not being exploitable?

Let me know if my read of what happened is wrong.

[–] 9029 2 days ago

It was serving static html https://news.ycombinator.com/item?id=50224916#50234806

[–] ericol 2 days ago

> claims they have an "universal" exploit

That's not correct. He claims they have A exploit. Based on the nature of the vuln, I assume every one that works in the are would be very careful to claim a universal exploit, and the comment by Mr. Guido seems to be align with that.

> This looks like a trap. We have a working RCE that would claim this, but I don't want to demonstrate that because it might leak what we built to others. We still have a window for people to patch and I don't want to risk that.

So what he seems to be saying (My interpretation) is "I don't want to demonstrate thus risking giving ideas to other people regarding hhow to build exploits"

The steal my bitcoin exploit works for a specific stak, and that is the reason why the person that set that up did publish certain information in the site itself (reduced phpinfo)

[–] nubinetwork 2 days ago

Just last week companies were saying php2shell has been rampant for months, but if that were the case, wouldn't we all have strange errors in our logs? Something seems fishy to me.

[–] minitech 2 days ago

Which companies? The earliest claim of an exploit attempt in the wild I had heard was October 17th, and that was “extant”, not “rampant”.

I don’t suppose you’re thinking of when the issue was discovered? That was August 1st, according to https://calif.io/php2shell/#the-discovery.

[–] nubinetwork 2 days ago

Amazon said 4 days prior to patch, but I'm pretty sure the other one was cloudflare, I can't find the link in my browser history.

[–] minitech 2 days ago

So was “months” a typo for “4 days” or what?

[–] makmanalp 2 days ago

Both of those are coming from telemetry, and mainly show attempts. Those telemetry are generally heuristic based so they overcount and are most often unsuccessful - it took much layer for actual honeypots to be hit. See my timeline in my other comment if you’re interested in details and extract dates

[–] red-iron-pine 2 days ago

4 days is a month now is it?

[–] jagged-chisel 2 days ago

Should we expect logs from a compromised system to be truthful?

[–] smolder 2 days ago

No, of course not. Covering your tracks by manipulating logs and monitoring tools is stuff any sophisticated attacker would do

[–] lambdaone 2 days ago

Perhaps if those logs were streamed to a non-compromised machine and stored there

[–] jagged-chisel 2 days ago

And how do we know the logs that are emitted are trustworthy?

[–] NorwegianDude 2 days ago

The steal my Bitcoin challenge was nothing like a realistic common PHP setup. It was a extremely unrealistic and stupid setup, using the built in php dev server. It's even explicitly stated that it should never be exposed to the internet.

If it needs to hit the same worker to get it to work, that is a whole other problem, and that was not a part of the steal my bitcoin challenge. And what if pm.max_requests is set to 1? Is it then 100 % safe, as it respawns for each requests, making any statement for an universal exploit completely BS, or is a single requests exploit possible?

[–] ericol 2 days ago

Preach, brother.

There's a difference between walking on the woods at night blind, and with a 20K lumens torchlight.

A successful universal exploit is all about making it land on the correct memory address for each set up, and that is nigh impossible.

As was stated by many groups that do this for a living (E.g., Crowdstrike) "PoC yes, RCE no"

Every single group I read published with the same caveats "RCE _in our labs_" as in, they knew a lot regarding the configuration of the system. Wiz themselves had an article out last week that stated "AI written, tread carefully" and almost all of them made no effort on distinguishing how the 2 vulns operated (Or, differed)

[–] nurettin 2 days ago

What have they done to earn 100% of your trust?

[–] idoubtit 2 days ago

As far as I know, there has been no proven vulnerability on a modern PHP (production) stack. The "Steal my Bitcoin" challenge was a toy project. The "lab" target used the embedded PHP server (`php -S`) which is for development only.

> Warning. This web server is designed to aid application development. [...] It should not be used on a public network. https://www.php.net/manual/en/features.commandline.webserver...

There are 3 main PHP interfaces (SAPI):

1. mod_php which is obsolete and requires Apache prefork (which should also be avoided)

2. php-fpm (FastCGI) which has been the default for more than a decade.

3. FrankenPHP is a new official interface much more suitable for containers.

There were 2 vulnerabilities.:

1. "OOM corruption". The advisory says there was a proven exploit with mod_php, but only for that obsolete SAPI. "Source analysis therefore supports FPM as a susceptible, though *no complete FPM exploit* has been demonstrated for this SAPI."

2. "stale global state". The advisory is The last PHP release (8.5) was vulnerable when the debug parameter fatal_error_backtraces was on. There was a suspicion that an exploit could exist in the session code for php-fpm, but it was unproven and probably unrealistic.

The "evidence" given at the end of the article seems old news to me. The honeypot was based on Apache-prefork + mod_php. As stated in the CVE, there is a proven exploit for that (obsolete) stack.