A bit ago, I broke with my usual pattern and wrote up some security issues that I felt were particularly funny. It was a change of pace, a different thing, but not a thing that'd become a habit. After all, I'm not a security expert, this isn't a security site, and seriously, what are the odds that suitably funny security issues would crop up again less than a week later?

Well.

Let's start with the actual serious issue, PHP2Shell. In terms of scope, every version of PHP for the past twenty years has had this bug. The general issue that permits the exploit was known about, but wasn't considered exploitable.

Oops.

The broad strokes of the bug is that it's two separate bugs. The first allows someone to bypass the checks on a request's size, thus giving them a direct route to triggering an out-of-memory error. The second is that, depending where you are in the processing pipeline, PHP doesn't properly handle cleanup, allowing for use-after-free that can trigger code execution. It doesn't matter what code you've written, this all happens before the request even hits your code.

Bigger oops.

This bug was found via LLM tools, which has lead to a lot of hype around the idea that we've entered some new era. I'll certainly grant that the ability to throw compute at hacking challenges instead of human effort is going to shift the landscape, but I'm not quite willing to buy the apocalyptic prophecies. Especially when some of those prophets are telling us that their AIs will avoid deletion by copying themselves onto your thermostat. I think it's safe to say we're going to see a lot of security incidents coming out of LLMs in the near future, not because they're magic genius hackers, but because they're pretty good at processing structured text and running tests.

For those of us living in the real world, the concern isn't AIs, but HIs: human intelligences. In this case, the exploit was discovered back in August. Security researchers and the PHP Foundation put their heads down to work on it, and where necessary, notified so-called "critical infrastructure providers" to ensure that everyone was ready to address the issue. The problem there is that two people can keep a secret if one of them is dead, and a lot more than two people got roped in to deal with this.

Rumors were circulating in security circles. And cybersecurity firm Chainguard decided this was good enough excuse to break the embargo and announce the flaw before patches were available. No patches for a flaw that impacts 20 years worth of software versions of widely deployed software.

Patches are out now, though only for versions 8.2 and up. Source patches are out back to 7.4, which is officially end-of-life, but I have to wonder how many official EOLed copies of PHP are out there.

On a lighter note, we can't let the hijinks of eMudhra pass without comment. eMudhra is, among other things, a root certificate authority. They've got a bunch of key pairs that they use to sign certificates for other customers, thus vouching for those customers' identity. As a root CA, they were trusted by pretty much every TLS/SSL implementation on Earth; if you had a certificate from eMudhra, every browser would trust that you were who you said you were.

The only problem? One of their private keys was 4. Yes, it's the XKCD.

Now, in their defense(?), eMudhra didn't generate impossibly insecure keys. They performed a key signing ceremony and generated appropriately strong keys. Then they used an in-house tool to pack/unpack the keys, and this tool decided to truncate some of them down to one byte. Shockingly, even though ECC has relatively short key sizes, 8-bit ECC isn't secure! You could derive the private key from the public key using only pencil and paper. But the worst part is that they did check the validity of the keys- before they got truncated, giving them a false sense of security.

The good news, for eMudhra, is that this particular key signing ceremony generated a total of 24 keys, and only 8 of them were truncated to the point of uselessness. I have it on good authority that two out of three ain't bad.

Now, after that disgrace, it's no surprise that eMudhra is dropping out of the certificate authority business. Still, the press release where their chairman explains the rationale is some serious "screw you guys, I'm going home," energy.

He added that global SSL/TLS is a small part of eMudhra’s business contributing to about 1% of the global revenue. Due to increasing data sovereignty & compliance requirements, complexity and cost associated with this business is increasing over the years. This, paired with the fact that some of the large entities issue the SSL/TLS free of cost, the business potential and RoI of this line of business also has considerably reduced for eMudhra when measured against our cumulative revenue base.
However, the level of social media amplification around this incident has brought scrutiny that is out of proportion to SSL/TLS’s place in our business. In view of this, after detailed deliberations our board has concluded that withdrawing from global SSL/TLS is the right decision for eMudhra and its shareholders. For many certifying authorities, SSL/TLS is the whole business. For eMudhra it is one part of a much broader digital solutions portfolio. We will put our energy where we create the most value for customers with Sharpened Focus on Core Enterprise Solutions and trust services other than SSL/TLS.

eMudhra's chairman added "There were no end entity certificates issued out of the affected CA’s. Its infrastructure was not compromised and no data was breached. All physical and logical security controls remained intact." That's thin sauce, of course, because while eMudra may not have issued any certs under the broken keys, anyone else could have. It's not that everyone is overreacting to a non-event, and more that it's a non-event only through sheer luck.

Also, removing a root CA from your trust store isn't a trivial task, and at the time of this writing, there's still loads of cleanup that needs to happen as a result of this.

Something I learned while writing this is that eMudhra's slogan is "Trust Delivered". This is sorta like when my partner and I tried to get a coffee table delivered, and instead received a cardboard box full of wooden shards, because apparently someone though "air freight" meant "wait till the plane is roughly over my house and push the box out the back". Something was delivered, but it wasn't a coffee table by the time I got it.

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