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Posts Tagged ‘Code signing’

Certificates From Leading Security Vendor Bit9 Used to Sign Malware

February 10, 2013 Leave a comment

Bit9Another high-profile security company has been breached. Bit9, a leading provider of application whitelisting technology, has admitted to have been attacked by a malicious external third party who was able to illegally gain access to one of their digital code-signing certificates. The attackers did not waste time and the compromised certificate has immediately been used to sign malware infiltrating, according to the company’s investigation, the network of three customers.

The news was initially revealed by Brian Krebs in a blog post, and later confirmed by the security vendor, which also gave additional (scant) details, including the fact that the malicious attackers were able to infiltrate a portion of their internal network not protected by their product.

We simply did not follow the best practices we recommend to our customers by making certain our product was on all physical and virtual machines within Bit9.

At first glance the attack has many points in common with the infamous RSA Breach of 2011, including the fact that maybe the real target of the attack was not the company itself, but the protected network of its customers. On the other hand, if it is true, as the company claims, that Bit9 was the only security company capable to stop both the Flame malware and the RSA breach attack, to achieve their target, the attackers had no other chance than attacking the source of their technology.

The latest demonstration, if necessary, that attacks are becoming more and more aggressive and sophisticated, and the protection is not only a matter of technology but even of good procedures and best practice, and not only for the possible victims…

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Adobe Persistent Threat

September 28, 2012 Leave a comment

Adobe is the latest victim of a targeted attack. The news has been reported in a blog post by Brad Arkin, Director of product security and privacy at Adobe.

According to Mr. Arking the company has recently received two malware strains in disguise of malicious utilities that appeared to be digitally signed using a valid Adobe code signing certificate and has identified the possible reason for the illegitimate code signing in a compromised build server with access to the Adobe code signing infrastructure as part of the build server.

The first malicious utility is called pwdump7 v7.1 and extracts password hashes from the Windows OS as a single file that statically links the OpenSSL library libeay32.dll.  The second malicious utility, dubbed myGeeksmail.dll, is a malicious ISAPI filter.

Of course the forensic investigation is ongoing. To date Adobe has identified the presence of malware on the build server (although the details of the machine’s configuration were not to Adobe corporate standards for a build server, this was not caught during the normal provisioning process”) and the likely mechanism used to first gain access. Although the forensic investigation has found evidence linking the build server to the signing of the malicious utilities, it appears that the private key required for generating valid digital signatures was not extracted from the HSM, which is kept in physically secure facilities. Even, so far there is no evidence that the source code was compromised or stolen.

As a natural consequence the company has changed the signing process and has deployed an interim solution including an offline human verification to ensure that all files scheduled for signature are valid Adobe software. Furthermore the company is also designing and deploying a new, permanent signing solution.

All the certificates signed with the impacted key since July 10, 2012 will be revoked on Thursday October 4, 2012 (does this means that the build server has been compromised, undetected, for more than two months?). Potentially there could be 5127 applications signed with the compromised key.

According to the available information, we are in front of a typical targeted attack:

We believe the threat actors established a foothold on a different Adobe machine and then leveraged standard advanced persistent threat (APT) tactics to gain access to the build server and request signatures for the malicious utilities from the code signing service via the standard protocol used for valid Adobe software.

Moreover “Targeted Attacks generate Targeted Attacks” since the malware samples discovered (most of all in case of the pwdump7 “utility”) show the typical features used by Advanced Persistent Threats: compromise one machine, extract information to escalate privileges (see password) and use the initial entry point as a bridgehead to harvest the target network.

So at the end Adobe is the latest high-profile target to join the group of the companies hit by targeted attack: “Through this process we learned a great deal about current issues with code signing and the impact of the inappropriate use of a code signing certificate. We plan to share our lessons learned as well as foster a conversation within the industry about the best way to protect users and minimize the impact on users in cases where the revocation of a certificate becomes necessary (as in this example).”

“Please stay tuned for more details in the coming weeks.”

First Security Breach In The App Store

November 8, 2011 Leave a comment

It looks like the Judgment Day for iOS has finally arrived. Until today the robustness of the AppStore has always been considered one of the strengths of the Apple Model: unlike the Android Market, which is constantly under attack for its weak security model that allowed too many malicious users to upload malicious applications, a strict control policy had prevented, at least so far, the same destiny for the mobile Apple Application.

Unfortunately Charlie Miller, an old acquaintance of the Apple Supporters, thought that winning three Pwn2Owns in the last four years (2008, 2009 and 2011) exploiting practically every Apple Vulnerability was not enough. So he decided consequently to attack Cupertino directly inside its AppStore security model.

The story begins early last year, after the release of iOS 4.3 when the researcher became suspicious of a possible flaw in the code signing of Apple’s mobile devices.

As stated in the original article by Forbes:

To increase the speed of the phone’s browser, Apple allowed javascript code from the Web to run on a much deeper level in the device’s memory than it had in previous versions of the operating system. In fact, the browser’s speed increase had forced Apple to create an exception for the browser to run unapproved code in a region of the device’s memory, which until then had been impossible. (Apple uses other security restrictions to prevent untrusted websites from using that exception to take control of the phone.)

The next step was to discover a bug that allowed to expand that code-running exception to any application, and that is exactly what he did, but still this was not enough.

After discovering the bug, he submitted an App to the App Store exploiting the vulnerability. The App was approved and behaved as expected (actually a behaviour to which the victims of Android malware are quite familiar): the app was able to phone home to a remote computer downloading new unapproved commands onto the device and executing them at will, including stealing the user’s photos, reading contacts, making the phone vibrate or play sounds, or otherwise repurposing normal iOS app functions for malicious ends.

This method will be presented at the SysCan Conference in Taiwan next week even if a video demonstrations of the exploit is already available.

Last but not least: as a reward for discovering the bug, Apple has decided to revoke to Miller the Developer’s License.

Probably Android users will be the happiest to learn that, as stated by Miller:

Android has been like the Wild West. And this bug basically reduces the security of iOS to that of Android.

At least for one thing (security), iOS and Android are identical.

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