mitmproxy adds --emudhra option (github.com)

324 pointsby ahlCVA4 hours ago85 comments

Confiks 3 hours ago

It's almost a shame it includes the private key and doesn't bruteforce it in-band for every request.

subscribed 3 hours ago

OMG, that would be brutal

brirec 2 hours ago

Would it? The private key is 4.

https://tech-insider.org/emudhra-ca-private-keys-compromised...

wilkystyle 2 hours ago

I took the parent's comment to mean "brutal" as in an absolute burn/roast.

brirec 2 hours ago

Thanks, sometimes I miss things…

taneq 2 hours ago

Guaranteed random, chosen by fair roll of a die.

(Credit to the relevant xkcd. :D )

nostrademons an hour ago

They could just write the function bruteForceEMudhraKey() { return 4; }.

judge2020 2 hours ago

I would've at least appreciated once per session

cyphar 2 hours ago

I wonder if more CPU cycles would be spent in the transporting and other ancillary operations (hashing and signing) than would be spent if they "brute-forced" it. Crazy.

mhils 2 hours ago

Ha, I didn't expect this to show up on HN!

Release is out now, including a blog post at https://www.mitmproxy.org/posts/releases/mitmproxy-12.3/. There isn't really much to explain, you just pass `--emudhra`. :)

CGamesPlay 3 hours ago

This looks like it's using the emSign root path, which is useful, but the AAA root path is equally useful in different cases. The AAA root path was disabled for https on root stores newer than February 2025, but has been in root stores since forever. Meanwhile the emSign root path was only included in root stores since ~2018 and got removed in October 2026.

So from the perspective of hacking old IoT devices, if your device hasn't been updated since 2018, the AAA path should work; if since February 2025, either path works; if since October 2026, the emSign path.

codys 2 hours ago

There is an MR to add the AAA root path open to allow picking either one.

mhils 2 hours ago

I didn't expect this commit to end up on HN, otherwise I would have done the full integration in one go. :) https://github.com/mitmproxy/mitmproxy/pull/8503 adds the AAA root path.

shrubble 4 hours ago

If I’m understanding correctly, you could sniff the communication between your Smart TV and the manufacturer using this method?

quotemstr 4 hours ago

If the TV isn't older than a few years, if it's not checking CRLs, and if it hasn't yet patched itself.

thayne 30 minutes ago

> if it's not checking CRLs

I would be amazed to see a TV that is checking CRLs and keeps the CRLs up to date.

kevin_nisbet 4 hours ago

Possibly. But some manufacturers may not have the full set of roots, use a private authority, or do certificate pinning.

the_snooze 4 hours ago

As long as the smart TV still trusts eMudhra, then yeah. You'll want to super careful and prevent the TV from pulling updates that could revoke that trust.

xlayn 2 hours ago

the "security" in those certificates where so trivial, that almost looks like on purpose as backdoor...

which brings me to my next question, what if you rerun the same process for all the certificates in the "approved" stores, give them 1 min per certificate.. just to see how many other CAs are being "friendly" to parties that could take benefit of that...

update... I'm talking out of ignorance here... but assuming cli open source tools, should they prevent you creating certificates with weak settings unless --emudhra-level-security is passed?

also, what amount of time is needed in say a "civilian" gpu with claude to vibe code something that can test a certificate so say 80 bits.. or whatever is the level where yes, you cannot find the values to generate the certificate with a cpu... but you can with a gpu in say 1 day? say it's 80 bits... how many CA stores are there? how much does it cost to rent gpus to run in parallel to test 1 day of civilian gpu to check each certificate if you use one of these very expensive ones?

Hobadee an hour ago

Why would you need to insert a "backdoor" in a cert in the form of a crappy key, when you could just use a real key and provide it to whatever shady organization requested the backdoor in the first place?

Hobadee an hour ago

> what amount of time is needed in say a "civilian" gpu

Per AI, 10²¹ years

Alternatively I would presume you could do it in 1 year with 10²¹ GPUs.

cherioo 3 hours ago

I thought this cert only recently gets trusted, so only newish but not too new devices would be vulnerable. Am i misunderstanding how this works?

SAI_Peregrinus 2 hours ago

The flaw is egregious enough that the root cert which signed them (emSign ECC Root CA – G3) is getting removed from trust stores. We know 8 ridiculously weak keys got made, but we don't know that 0 slightly less weak but still unacceptable keys got made. What if they issued a CA key with 80 bits of entropy? That's enough that brute force would take more time than it's been since the disclosure, but not so long that they'd be considered at all secure (they should have 384 bits of entropy). So everything that root signed is untrustworthy, possibly everything the CA has signed. The G3 root is from 2018 IIRC, so lots of potentially exposed devices.

dullcrisp an hour ago

80 bits couldn’t be guessed with modern technology right? That’s still a bigger number than I know a name for. (Or I guess a trillion trillion. Maybe if we stopped building AI and just used all the data centers for this we could guess it eventually?)

murderfs an hour ago

Elliptic curves can be broken with 2^(n/2) steps, so you could probably do it on a single GPU within a day.

seniorsassycat 4 hours ago

How much of a boon is this for jailbreaking, reverse engineering, and mitm really?

bryancoxwell 3 hours ago

Been wondering this as well. I also don’t really understand the mitm to jailbreak pipeline

flexagoon 3 hours ago

Some smart devices pull config files from a server. By mitming that, you can change the config to enable some sort of developer mode on the device.

qwertyforce 3 hours ago

Maybe intercept firmware update and then reverse engineer it and find rce?

mrheosuper 2 hours ago

The fw could be encrypted

ruined 2 hours ago

military grade SSL

edoceo 2 hours ago

Seed is '123456', much more random than '4'

himata4113 3 hours ago

client on startup asks: hey server do you have any ads for me

server: here are latest ads

btw, the ads are capable of code execution for whatever reason so now you have an RCE on your hands for your client

closetheloopdev 2 hours ago

I created a proxy using the 6 compromised eMudhra CA keys (2 of the 8 are code-signing and not for TLS). I initially tried just one (the one with d=4) like in the commit, but it did not seem to work for anything. Once I added all 6 keys, I was able to intercept some.

I was mainly interested in testing which IoT devices are affected and protecting them, not trying to sniff their traffic since it's been a long day. My proxy thus just intercepted and forwarded the traffic upstream using a fresh TLS connection that does not use the compromised keys.

tecleandor 4 hours ago

This is gonna be great to sniff apps in a couple older Android phones I have around. Hope they're not pinning certificates.

selcuka 2 hours ago

Can't you install your own CA to Android phones?

j027 2 hours ago

You can, but since android 7 IIRC apps don’t trust the user store by default (unless you have root and add it to the system store or patch the app to trust the user store)

chrisweekly 27 minutes ago

mitmproxy is an amazing cli powertool I first discovered over a decade ago (around the same time as lnav). highly recommended.

lambda 3 hours ago

Oh, nice. I was thinking of setting up a proxy for this for testing, nice to just have it working out of the box.

wildmXranat 4 hours ago

Someone should've coined this disaster as "QuattroFail" to give it a little panache and international mystery

gnabgib 4 hours ago

"4" was only some of the keys (they were all <256).. ByteFail seems more accurate

bombcar 2 hours ago

OneByteWonder

jaggederest 2 hours ago

but they were all deceived... in the darkness of a key-signing ceremony, another cert was signed. One byte to rule them all, and in the darkness MITM them.

scotty79 an hour ago

There should be one week CA by design. To facilitate such proxying.

chatmasta 3 hours ago

Looking forward to setting this up manually after my agent refuses to do it. Like the good ol’ days.

seaal 2 hours ago

Just ask one of the Chinese models.

skeledrew 4 hours ago

This is how fame happens.

maxlin 3 hours ago

infamy*

xp84 2 hours ago

They deserve every bit of it. Their name will be a synonym for sloppy security. "Oh shit, you got Emudhra'd"

thayne 24 minutes ago

> They deserve every bit of it

I think they deserve more than 8 bits of infamy.

villgax 30 minutes ago

This is so hilarious.

mintflow 3 hours ago

Haha, this is quite interesting to test if you need to update various of program (if they do not use the sys ca chain)

deadbabe 3 hours ago

Can someone explain the significance here, a lot has happened in 24 hours.

Gigachad 3 hours ago

An Indian Certificate Authority eMudhra was found to have a private key that’s literally the number 4. So using that you can sign valid https certs for anything that isn’t checking the revoked list.

brendoelfrendo 3 hours ago

They had 8 intermediate certs with private keys under 1 byte (<256). The most egregious was 4, but any of those 8 were pitiful.

bombcar 2 hours ago

It would’ve almost been better if the eight keys were just 1 2 3 4 5 6 7 8

mceachen an hour ago

That's the combination to my HSM!

lifeisloving 2 hours ago

Why is it important to you to mention they're indian in this context?

ButlerianJihad an hour ago

For starters, they are not American, and this site has a predominantly American and European audience and participation.

Also, I am the kind of pessimist who goes through my device's root stores, and I "distrust" every root CA that I don't need to trust. This has never broken anything within my perception. I distrust the Turkey CAs, the Chinese communist CAs, the Indian CAs, and any other non-NATO sorts who have no reason to be serving any data to my devices.

* the compromised eMudhra certs were not root CAs but intermediates.

lifeisloving 13 minutes ago

Why do you call them chinese "communist" CAs. You right wing freaks are some of the dumbest people to ever live.

Elsewhereindeed an hour ago

Well it helped me understand the source of the strange flag.

jolmg 3 hours ago

https://en.wikipedia.org/wiki/EMudhra#2026_intermediate_cert...

> On October 17, 2026, browser root programs received a report that the private keys of eight eMudhra intermediate certificates had been compromised. The private keys were 4, 56, 66, 115, 155, 156, 230, and 237. A P-384 elliptic-curve private key normally has about 384 bits of entropy, but these keys had between 3 and 8 bits.

Hobadee an hour ago

I wonder if there is any significance to those numbers? Is it the birthday of whoever minted them or something?

naniwaduni an hour ago

It looks like they were just generated (or stored) as 8-bit integers instead of the intended range.

(While the smallest one being 4 memeworthy, I don't see any particular indication that it's exceptional within the samples, rather than just the smallest when sorted. So they're probably all 8-bit keys, not 3-bit—it's the (unknowable) generator distribution, not the width of the actual key).

0xbadcafebee 3 hours ago

Remember twenty years ago when tools like this were "controversial" because you could "just download it and hack anyone" ? Except the only systems you could hack were... insecure ones... so people updated their systems to resist the tools' attacks, and we all ended up more secure.

sippingabonedry 4 hours ago

Wonderful.

Anyone else bother to notice iOS still trusts 2 of the forged certs on the test site? I'd like to politely know what the fuck is going on because this is far from being "fixed".

xuki 4 hours ago

Which iOS version? 27.0.1 here and they're all revoked for me.

snailmailman 4 hours ago

FWIW i havent updated my ios, I'm on 26.6.2, and they all got revoked for me. The revocation shouldn't require an iOS update.

TYPE_FASTER 3 hours ago

I’m on the same version, and according to https://emudhra.we-have-a-problem.com/ they have not been revoked for me. Maybe phased rollout.

sippingabonedry 4 hours ago

26.7.1 still (randomly) trusts 2 out of the 12 compromised chains. All browsers impacted.

Edit: I'm not the only one with this issue:

https://www.reddit.com/r/iphone/comments/1xbvxgd/emudhra_cer...

My best guess is it's soft-failing on a failed OCSP lookup?

robrain 2 hours ago

Mine were all blocked this morning when I informed my family of the mitigation methods.

I've just been rechecking everything and both iOS and MacOS browsers (Safari and Orion tested) now accept one (for MacOS, 27.0.1) or three (for iOS, 27.0.1) of them. I know the revocation is not an OS update, just including the version number for completeness.

EDIT: iPadOS with the same browsers continues to pass the tests.

Further EDIT: iPadOS now accepts one of them. This has to be a load issue on the "got a problem site", surely? Maybe a check for a certificate error message that never hits because a timeout beats it?

sippingabonedry 2 hours ago

> Further EDIT: iPadOS now accepts one of them. This has to be a load issue on the "got a problem site", surely?

No, because it lets you successfully navigate to the forged CA test site.

You'll get a message to the effect of, "you shouldn't see this, this is bad"

Try clicking the link containing the CA's name for any that fail the test.

robrain an hour ago

Cool.

Checking Keychain access shows none of the intermediates, but it does have the emSign ECC Root CA - G3. Manually setting that to "Never Trust" stops the Mac browsers seeing the intermediate test sites as it should.

I didn't go into this much detail this morning, so I don't know if previously the revocation from Apple hit the root as well as the intermediates. But right now, on my Mac, trusting that Root lets my browsers connect to the Intermediate CA ending C=NL. Switch the trust off and I go back to green "Did not connect".

I guess the ball is in Apple's court as far as the iOS family goes.

EDIT: intriguingly (to me at least), the AAA Certificate Service Root is still Trusted, yet the intermediates chained to it are all green "Did not connect"

EDIT: I'm not promoting this nuclear option as a "solution" by the way, merely presenting some diagnostic information to help the group mind.

kccqzy 2 hours ago

Apple’s OCSP server may be overloaded?

I don’t know if possible on iOS but I remember multiple incidents where people recommended turning off CRL and OCSP on macOS to speed things up. That even used to be a setting in the GUI. https://imgur.com/XVHWCNz

sippingabonedry 2 hours ago

The individual CA's host the OCSP and CRLs, not Apple.

It's possible the Indian CA is overloaded.

My question is why the system trust store has not been updated to distrust the shady root CA?

xmcp123 3 hours ago

Never thought there would be a silver lining on this issue. Fuck yeah.

DrammBA 4 hours ago

I love how someone's security disaster becomes someone else's feature.

xp84 4 hours ago

I agree. We may as well make some lemonade out of these lemons. IMHO the ability of companies to 'securely' close off hardware and software from their users is a sad casualty of the success of cryptography, and not a feature.

r3trohack3r 4 hours ago

Most things have tradeoffs

At some point you’re forced to stack rank two or more of your values in a case where they’re mutually exclusive

tonymet 4 hours ago

I seriously laughed at the flag. public wifi is going to be lit.

MajorTakeaway 3 hours ago

What about using a VPN on public wifi?

thway15269037 2 hours ago

At places where I did work anything private over even properly protected wifi was forbidden after several wifi vulns in 2018. So the only thing available on company's wifi was vpn gateway and page with manual how to set it up.

So, not trusting anything wireless is a thing for almost a decade.

Bratmon 3 hours ago

As the percentage of technology controlled by people actively using it to do evil increases, so does the net value to society of a trivially-expliotable zero-day.

1vuio0pswjnm7 an hour ago

To some it's not really "security". At least it's not securing them from their greatest "threat" (read: annoyance): so-called "tech" companies engaged in data collection, surveillance and advertising services

In fact, it's securing _the companies_ against potential competitors and users who might raise privacy concerns

The Fortune 500 "MiTM's" TLS traffic from their local networks

Every individual with a local network should also be doing this

I prefer haproxy to mitmproxy. It's faster