This Week In Security: It’s Con Season

It must be Blackhat/DEFCON season. Up first in the storm of named vulnerabilities, we have Downfall. The PDF has the juicy details here. It’s quite similar to the Zenbleed issue from last week, in that it abuses speculative execution to leak data via a hidden register. Unlike Zenbleed, this isn’t direct access, but using cache timing analysis to extract individual bytes using a FLUSH+RELOAD approach.

The key to the vulnerability is the gather instruction, which pulls data from multiple locations in memory, often used to run a followup instruction on multiple bytes of data at once. The gather instruction is complex, takes multiple clock cycles to execute, and uses several tricks to execute faster, including managing buffers to avoid multiple reads. In certain cases, that instruction can be interrupted before it completes, leaving the data in the cache. And this data can be speculatively accessed and the values leaked through timing analysis.

This flaw affects 6th generation Intel Core processors through 11th. Mitigations are already rolling out via a microcode update, but do carry a performance hit for gather instructions. Continue reading “This Week In Security: It’s Con Season”

Revisiting The BlackHat Hack: How A Security Conference Was Pwned

Does anyone remember the Black Hat BCard hack in 2018? This hack has been documented extensively, most notoriously by [NinjaStyle] in his original blog post revealing the circumstances around discovering the vulnerability. The breach ended up revealing the names, email addresses, phone numbers, and personal details of every single conference attendee – an embarrassing leak from one of the world’s largest cybersecurity conferences.

To recap: The Black Hat conference badges included an embedded NFC tag storing the participant’s contact details presumably for vendors to scan for marketing purposes. After scanning the tag, [NinjaStyle] realized that his name was readily available, but not his email address and other information. Instead, the NFC reader pointed to the BCard app – an application created for reading business cards.

[NinjaStyle] decompiled the APK for the app to search for API endpoints and found that the participants each had a custom URL made using event identification values. After finding data that appeared to correspond to an eventID and badgeID, he sent a request over a web browser and found that his attendee data was returned completely unauthenticated. With this knowledge, it was possible to brute-force the contact details for every Black Hat attendee (the range of valid IDs was between 100000-999999, and there were about 18,000 attendees). Using Burp Suite, the task would take about six hours. 

He was able to get ahold of BCard to reveal the vulnerability, which was fixed in less than a day by disabling the leaky API from their legacy system. Even so, legacy APIs in conference apps aren’t an uncommon occurrence – the 2018 RSA Conference (another cybersecurity conference) also suffered from an unprotected app that allowed 114 attendee records to be accessed without permission.

With the widespread publicity of leaked attendee data, event organizers are hopefully getting smarter about the apps that they use, especially if they come from a third-party vendor. [Yashvier Kosaraju] gave a talk at TROOPERS19 about pen testing several large vendors and discovering that Kitapps (Attendify) and Eventmobi both built apps with unauthenticated access to attendee data. It’s hard to say how many apps from previous years are still around, or whether or not the next event app you use will come with authentication – just remember to stay vigilant and to not give too much of your personal data away.

This Week In Security: Black Hat, DEF CON, And Patch Tuesday

Blackhat and DEF CON both just wrapped, and Patch Tuesday was this week. We have a bunch of stories to cover today.

First some light-hearted shenanigans. Obviously inspired by Little Bobby Tables, Droogie applied for the vanity plate “NULL”. A year went by without any problems, but soon enough it was time to renew his registration. The online registration form refused to acknowledge “NULL” as a valid license plate. The hilarity didn’t really start until he got a parking ticket, and received a bill for $12,000. It seems that the California parking ticket collection system can’t properly differentiate between “NULL” and a null value, and so every ticket without a license plate is now unintentionally linked to his plate.

In the comments on the Ars Technica article, it was suggested that “NULL” simply be added to the list of disallowed vanity plates. A savvy reader pointed out that the system that tracks disallowed plates would probably similarly choke on a “NULL” value.

Hacking an F-15

In a surprising move, Air Force officials brought samples of the Trusted Aircraft Information Download Station (TADS) from an F-15 to DEF CON. Researchers were apparently able to compromise those devices in a myriad of ways. This is a radical departure from the security-through-obscurity approach that has characterized the U.S. military for years.

Next year’s DEF CON involvement promises to be even better as the Air Force plans to bring researchers out to an actual aircraft, inviting them to compromise it in every way imaginable.

Patch Tuesday

Microsoft’s monthly dump of Windows security fixes landed this week, and it was a doozy. First up are a pair of remotely exploitable Remote Desktop vulnerabilities, CVE-2019-1222 and CVE-2019-1226. It’s been theorized that these bugs were found as part of an RDP code review launched in response to the BlueKeep vulnerability from earlier this year. The important difference here is that these bugs affect multiple versions of Windows, up to and including Windows 10.

What the CTF

Remember Tavis Ormandy and his Notepad attack? We finally have the rest of the story! Go read the whole thing, it’s a great tale of finding something strange, and then pulling it apart looking for vulnerabilities.

Microsoft Windows has a module, MSCTF, that is part of the Text Services Framework. What does the CTF acronym even stand for? That’s not clear. It seems that CTF is responsible for handling keyboard layouts, and translating keystrokes based on what keyboard type is selected. What is also clear is that every time an application builds a window, that application also connects to a CTF process. CTF has been a part of Microsoft’s code base since at least 2001, with relatively few code changes since then.

CTF doesn’t do any validation, so an attacker can connect to the CTF service and claim to be any process. Tavis discovered he could effectively attempt to call arbitrary function pointers of any program talking to the same CTF service. Due to some additional security measures built into modern Windows, the path to an actual compromise is rather convoluted, but by the end of the day, any CFT client can be compromised, including notepad.

The most interesting CFT client Tavis found was the login screen. The exploit he demos as part of the write-up is to lock the computer, and then compromise the login in order to spawn a process with system privileges.

The presence of this unknown service running on every Windows machine is just another reminder that operating systems should be open source.

Biostar 2

Biostar 2 is a centralized biometric access control system in use by thousands of organizations and many countries around the globe. A pair of Israeli security researchers discovered that the central database that controls the entire system was unencrypted and unsecured. 23 Gigabytes of security data was available, including over a million fingerprints. This data was stored in the clear, rather than properly hashed, so passwords and fingerprints were directly leaked as a result. This data seems to have been made available through an Elasticsearch instance that was directly exposed to the internet, and was found through port scanning.

If you have any exposure to Biostar 2 systems, you need to assume your data has been compromised. While passwords can be changed, fingerprints are forever. As biometric authentication becomes more widespread, this is an unexplored side effect.


Gigabytes The Dust With UEFI Vulnerabilities

At this year’s BlackHat Asia security conference, researchers from Cylance disclosed two potentially fatal flaws in the UEFI firmware of Gigabyte BRIX small computers which allow a would-be attacker unfettered low-level access to the computer.

Gigabyte has been working on a fix since the start of 2017. Gigabyte are preparing to release firmware updates as a matter of urgency to only one of the affected models — GB-BSi7H-6500 (firmware vF6), while leaving the — GB-BXi7-5775 (firmware vF2) unpatched as it has reached it’s end of life. We understand that support can’t last forever, but if you sell products with such a big fault from the factory, it might be worth it to fix the problem and keep your reputation.

The two vulnerabilities that have been discovered seem like a massive oversight from Gigabyte, They didn’t enable write protection for their UEFI (CVE-2017-3197), and seem to have thrown cryptography out of the window when it comes to signing their UEFI files (CVE-2017-3198). The latter vulnerability is partly due to not verifying a checksum or using HTTPS in the firmware update process, instead using its insecure sibling HTTP. CERT has issued an official vulnerability note (VU#507496) for both flaws.

Attackers may exploit the vulnerabilities to execute unsigned code in System Management Mode (SMM), planting whatever malware they like into the low level workings of the computer. Cylance explain a possible scenario as follows:

The attacker gains user-mode execution through an application vulnerability such as a browser exploit or a malicious Word document with an embedded script. From there, the attacker elevates his privileges by exploiting the kernel or a kernel module such as Capcom.sys to execute code in ring 0. A vulnerable SMI handler allows the attacker to execute code in SMM mode (ring -2) where he finally can bypass any write protection mechanisms and install a backdoor into the system’s firmware.

With all this said, it does raise some interesting opportunities for the hacker community. We wonder if anyone will come up with a custom UEFI for the Brix since Gigabyte left the keys in the door.

Network Security Theatre

Summer is nearly here, and with that comes the preparations for the largest gathering of security researchers on the planet. In early August, researchers, geeks, nerds, and other extremely cool people will descend upon the high desert of Las Vegas, Nevada to discuss the vulnerabilities of software, the exploits of hardware, and the questionable activities of government entities. This is Black Hat and DEF CON, when taken together it’s the largest security conference on the planet.

These conferences serve a very important purpose. Unlike academia, security professionals don’t make a name for themselves by publishing in journals. The pecking order of the security world is determined at these talks. The best talks, and the best media coverage command higher consultancy fees. It’s an economy, and of course there will always be people ready to game the system.

Like academia, these talks are peer-reviewed. Press releases given before the talks are not, and between the knowledge of security researchers and the tech press is network security theatre. In this network security theatre, you don’t really need an interesting exploit, technique, or device, you just need to convince the right people you have one.

Continue reading “Network Security Theatre”

BadUSB Means We’re All Screwed

Does anyone else get the feeling that the frequency of rather horrible vulnerabilities coming to light is accelerating? Off the top of our head, there’s Heartbleed, Shellshock, and now this one. The BadUSB exploit attack stems from the “invisible” microcontroller in most USB devices.

We first heard about it when we were attending DEFCON in August. The exploit had been announced the same week at Blackhat but there wasn’t much information out yet. Now the talk has been posted and there’s a well-explained overview article at Big Mess o’ Wires.

Here’s how this one goes: all USB devices rely on a microcontroller to handle the peripheral-side of USB communications. The computer doesn’t care which microcontroller, nor does it have a way of knowing even if it wanted to. The uC is “invisible” in this situation, it’s the interface and data flowing through it that the computer cares about. BadUSB is an attack that adds malicious functionality to this microcontroller. To the computer it’s a perfectly normal and functional USB device, while all the bad stuff is happening on the peripheral’s controller where the computer can’t see it.


How deeply do you think about plugging each and every USB device? Check out what happens at 19:20 into the video below. The USB device enumerates and very quickly sets up a spoofed Ethernet connection. You can still load a webpage via WiFi but the fake connection is forwarding packets to a second server.

Once discovered, you can wipe the computer and this will stop happening; until you plug the same device again and reinfect. Worse yet, because the controller is invisible to the computer there’s almost no way to scan for infected devices. If you are smart enough to suspect BadUSB, how long will it take you to figure out if its your mouse, your keyboard, a thumb drive, a webcam, your scanner… you get the point.

Continue reading “BadUSB Means We’re All Screwed”

Blackhat: IOS Device Charger Exploit Installs And Activates Malware


A team of researchers from Georgia Tech unveiled their findings yesterday at the Blackhat conference. Their topic is a power charger exploit that installs malware on iOS devices. Who would have thought that there’d be a security hole associated with the charging port on a device? Oh wait, after seeing hotel room locks exploited through their power jack this is an avenue that should be examined with all device security.

The demonstration used a charger and an BeagleBoard. Plugging in the charger is not enough to trigger the exploit, the user must unlock the screen while charging for it to go into action. But once that’s done the game is over. Their demo removes the Facebook app and replaces it with an infected impostor while leaving the icon in the same place on your home screen. They notified Apple of their findings and a patch will roll out with iOS7. So when would you plug your device into an untrusted charger? Their research includes a photo from an airport where an iPad is connected to the USB port of a public charging station.

The summary on the Blackhat site has download icons for the white paper and presentation slides. At the time of writing we had a hard time getting them to download but succeeded after several tries.