Cydia Package isslfix Fixes SSL Vulnerability For iOS < 4.3.5

[Joshua Tucker]

With the release of JailbreakMe 3.0 and Apple's response, iOS has been updated twice in order to patch the JailbreakMe exploit and other vulnerabilities. As mentioned in the iOS 4.3.4 article, updating to iOS 4.3.4 is not recommended as it only fixes the PDF exploit that JailbreakMe used. From there, Apple once again released a new version, 4.3.5, to patch other issues that were found. Although redsn0w is now able to jailbreak both 4.3.4 and 4.3.5, it is also not recommended as you will have to deal with a tethered jailbreak.

Now: In Apple's current releases, there were things that were patched that were actually "legitimate" fixes (not in response to JailbreakMe 3.0). The problem is, if you're sticking jailbroken, you aren't able to get this security updates without having to upgrade and lose an untethered jailbreak. This issue has now been solved by jan0 (@0naj) who recently released a package called "isslfix" on Cydia.

In the most basic terms, isslfix patches an SSL vulnerability known as CVE-2011-0228 without having to upgrade to the latest firmwares. All you simply need to do is install isslfix from Cydia and you will have the same protection that the later iOS firmwares offer.

More detailed information can be found at jan0's GitHub page, along with information on how to check to see if you're vulnerable or not and how to deal with issues if they do arise.

Read this article from The Recurity Lablog that explains the CVE-2011-0228 vulnerability:

You have two options to install isslfix:

• Install isslfix directly off Cydia from the BigBoss repo
• Install the isslfix .deb file and follow the installation instructions in the Readme on the GitHub page

Note: Rebooting your device will be required after installation.

To test and see if you're vulnerable (or if you're protected with this package), visit the following website on your iDevice:

https://issl.recurity.com/

If what comes up looks anything like the picture below (showing the HTTPS), you're vulnerable.



However, if it gives you a warning and a "Continue" screen before viewing the page, that means you're protected.

Note: The iOS 5 beta already patches this so there is no need to install isslfix on any iOS 5 beta firmware.

If you wish to read support documents from Apple discussing the different security updates from the firmwares at hand, read below:

iOS 4.3.4
iOS 4.3.5

Keep up to date on information about this new fix by following jan0 on Twitter.

Source(s): jan0 - GitHub, jan0, Apple, The Recurity Lablog

[luvmytj]

Nice work!

[Hosko817]

can somebody explain this in plain English if this is a necessary fix and why?

[wohhey]

can somebody explain this in plain English if this is a necessary fix and why?

Someone can hack your iDevice? I think itīs recommended to install this fix if you are on iOS 4.3.3 and jailbroken.

[Italia411]

I keep getting the server can not be found when I try and access the link above.

[raduga]

Someone can hack your iDevice? I think itīs recommended to install this fix if you are on iOS 4.3.3 and jailbroken.

I'd recommend that you install, if you are on iOS 4.3.3 or earlier, whether you're jailbroken or not.
Though, only jb people are actually able to :/

[Mes]

Nice work 0naj

And nice write-up Josh

[Joshua Tucker]

Nice work 0naj

And nice write-up Josh

Thanks my good sir. I agree, awesome job 0naj!

[that_girl]

Nicely done! It works!

[Orby]

This package is now available on BigBoss...

Click me on your jailbroken iDevice!

This exploit is based off the fact that intermediate X.509 certificates are not fully validated by iOS before being declared valid--specifically the "Basic Constraints" field.

One of the X.509 certificate's fields is "Basic Constraints" which contains things such as what the certificate is valid for (e.g., code signature, S/MIME, SSL/TLS, etc.) and whether or not the certificate represents a Certificate Authority.

The iSSL certificate (issued by iCA, one of Apple's cert authorities) Basic Constraints field reads:

Not Critical
Is a Certificate Authority
Maximum number of intermediate CAs: unlimited

Apple did NOT sign a certificate like that. It was edited by the hackers; thereby breaking the original signature on the certificate. However, since iOS didn't check that signature, this certificate was accepted as valid.

Since all iOS applications rely on the same framework (securityd) to access SSL/TLS connections, one fake certificate, set to accept any server (*.*, *.*.* etc.) could be used to intercept any and all data sent by the iPhone to a server of the exploiter's choice (a Man in the Middle attack).

[R.Mortera]

Thanks, downloaded the pkg, checked and not vulnerable. (it asked to continue)

[mmaboi21]

I am so glad that the updates in the future will not rely on restore's.
Nice work

[xclusiveiphone]

I get 403 forbidden error. Am I protected?

[Mes]

I get 403 forbidden error. Am I protected?

Try using https (not http)

... (a Man in the Middle attack).

You're the man

[GenesisDH]

Note about iOS5 beta part of the OP: If you are on iOS beta 3 or lower jailbroken (some JB-ed 3GS with the 6.15.00 iPad baseband can't do beta 4-5 until SB is updated), then you're still vulnerable and should also install this patch.

I tried the site and found it to be true for beta 3.

[ActionMax09]

I keep getting the server can not be found when I try and access the link above.

Me as well, you are not alone.

[kschong710]

i using 4.3.3 JB and just follow install issl.recurity
the outcome is same with the image that post.
without error did it mean i`m vulnerable?

[ronw]

i using 4.3.3 JB and just follow install issl.recurity
the outcome is same with the image that post.
without error did it mean i`m vulnerable?

Wierd cuz I'm experiencing the same issue. I checked that page first to confirm I was volnerable then installed which forced reboot but still get page wo it asking to continue or not

Wierd cuz I'm experiencing the same issue. I checked that page first to confirm I was volnerable then installed which forced reboot but still get page wo it asking to continue or not

Nm, cleared history and closed old page and it worked fine

[Mista Brothason]

Should we install if we're on 4.2.1?

[xclusiveiphone]

Should we install if we're on 4.2.1?

Yes, but I'm not quite sure if it will add more "security" to our phones.