This Week in Security

238 Articles

This Week In Security: TPM And BootGuard, Drones, And Coverups

May 12, 2023 by 17 Comments

Full disk encryption is the go-to solution for hardening a laptop against the worst-case scenario of physical access. One way that encryption can be managed is through a Trusted Platform Module (TPM), a chip on the motherboard that manages the disk encryption key, and only hands it over for boot after the user has authenticated. We’ve seen some clever tricks deployed against these discrete TPMs, like sniffing the data going over the physical traces. So in theory, an integrated TPM might be more secure. Such a technique does exist, going by the name fTPM, or firmware TPM. It uses a Trusted Execution Environment, a TEE, to store and run the TPM code. And there’s another clever attack against that concept (PDF).

It’s chip glitching via a voltage fault. This particular attack works against AMD processors, and the voltage fault is triggered by injecting commands into the Serial Voltage Identification Interface 2.0 (SVI2). Dropping the voltage momentarily to the AMD Secure Processor (AMD-SP) can cause a key verification step to succeed even against an untrusted key, bypassing the need for an AMD Root Key (ARK) signed board firmware. That’s not a simple process, and pulling it off takes about $200 of gear, and about 3 hours. This exposes the CPU-unique seed, the board NVRAM, and all the protected TPM objects.

So how bad is this in the real world? If your disk encryption only relies on an fTPM, it’s pretty bad. The attack exposes that key and breaks encryption. For something like BitLocker that can also use a PIN, it’s a bit better, though to really offer more resistance, that needs to be a really long PIN: a 10 digit PIN falls to a GPU in just 4 minutes, in this scenario where it can be attacked offline. There is an obscure way to enable an “enhanced PIN”, a password, which makes that offline attack impractical with a secure password.

And if hardware glitching a computer seems to complicated, why not just use the leaked MSI keys? Now to be fair, this only seems to allow a bypass of Intel’s BootGuard, but it’s still a blow. MSI suffered a ransomware-style breach in March, but rather than encrypt data, the attackers simply threatened to release the copied data to the world. MSI apparently refused to pay up, and source code and signing keys are now floating in the dark corners of the Internet. There have been suggestions that this leak impacts the entire line of Intel processors, but it seems likely that MSI only had their own signing keys to lose. But that’s plenty bad, given the lack of a revocation system or automatic update procedure for MSI firmware. Continue reading “This Week In Security: TPM And BootGuard, Drones, And Coverups” →

This Week In Security: Oracle Opera, Passkeys, And AirTag RFC

May 5, 2023 by 10 Comments

There’s a problem with Opera. No, not that kind of opera. The Oracle kind. Oracle OPERA is a Property Management Solution (PMS) that is in use in a bunch of big-name hotels around the world. The PMS is the system that handles reservations and check-ins, talks to the phone system to put room extensions in the proper state, and generally runs the back-end of the property. It’s old code, and handles a bunch of tasks. And researchers at Assetnote found a serious vulnerability. CVE-2023-21932 is an arbitrary file upload issue, and rates at least a 7.2 CVSS.

It’s a tricky one, where the code does all the right things, but gets the steps out of order. Two parameters, jndiname and username are encrypted for transport, and the sanitization step happens before decryption. The username parameter receives no further sanitization, and is vulnerable to path traversal injection. There are two restrictions to exploitation. The string encryption has to be valid, and the request has to include a valid Java Naming and Directory Interface (JNDI) name. It looks like these are the issues leading Oracle to consider this flaw “difficult to exploit vulnerability allows high privileged attacker…”.

The only problem is that the encryption key is global and static. It was pretty straightforward to reverse engineer the encryption routine. And JDNI strings can be fetched anonymously from a trio of endpoints. This lead Assetnote to conclude that Oracle’s understanding of the flaw is faulty, and a much higher CVSS score is appropriate. Particularly with this Proof of Concept code, it is relatively straightforward to upload a web shell to an Opera system.

The one caveat there is that an attacker has to get network access to that install. These aren’t systems intended to be exposed to the internet, and my experience is that they are always on a dedicated network connection, not connected to the rest of the office network. Even the interconnect between the PMS and phone system is done via a serial connection, making this network flaw particularly hard to get to. Continue reading “This Week In Security: Oracle Opera, Passkeys, And AirTag RFC” →

This Week In Security: Session Puzzling, Session Keys, And Speculation

April 28, 2023 by 7 Comments

Last week we briefly mentioned a vulnerability in the Papercut software, and more details and a proof of concept have been published. The vulnerability is one known as session puzzling. That’s essentially where a session variable is used for multiple purposes, or gets incorrectly set. In Papercut, it was possible to trigger the SetupCompleted class on a server that had already finished that initial setup process. And part of SetupCompleted validated the session of the current user. In a normal first-setup case, that might make sense, but as anyone could trigger that code, it allowed anonymous users to jump straight to admin.

The other half of the exploit leverages the “print script” feature, which lets admins write code that runs on printing. A simple java.lang.Runtime.getRuntime().exec('calc.exe'); does the trick to jump from web interface to remote code execution. The indicators of compromise are reasonable generic, including User "admin" logged into the administration interface. and Admin user "admin" modified the print script on printer "".. A Shodan search turns up around 1,700 Papercut servers accessible from the Internet, which prompts the painfully obvious observation that your internal print auditing solution’s web interface definitely should not be exposed online.

Apache Superset

Superset is a nifty data visualization tool for showing charts, graphs, and all sorts of pretty data sets on a dashboard. It also has some weirdness with using web sessions for user management. The session is stored on the user side in a cookie, signed with a secret key. This works great, unless the key used is particularly weak. And guess what, the default configuration of Superset uses a pre-populated secret key. thisismysecretkey is arguably a bad key to start with, but it turns out it’s also shared by more than 70% of the accessible Superset servers.

Continue reading “This Week In Security: Session Puzzling, Session Keys, And Speculation” →

This Week In Security: Spandex Tempest, Supply Chain Chain, And NTP

April 21, 2023 by 14 Comments

Microsoft’s Threat Intelligence group has announced a new naming scheme for threat actors. It sounds great, naming groups after weather phenomenon, based on the groups motivations or nation of origin. Then each discreet group is given an additional adjective. That’s where things get interesting.

It seems like the adjectives were chosen at random, giving rise for some suitably impressive names, like Ghost Blizzard, Ruby Sleet, or Granite Typhoon. Some of the other names sound like they should be desserts: Caramel Tsunami, Peach Sandstorm, Aqua Blizzard, or Raspberry Typhoon. But then there the really special names, like Wine Tempest and Zigzag Hail. But the absolute winner is Spandex Tempest. No word yet on whether researchers managed to keep a straight face when approving that name.

Chrome 0-day Double

A pair of Chrome browser releases have been minted in the past week, both to address vulnerabilities that are actively being exploited. Up first was CVE-2022-2033, type confusion in the V8 JS engine. That flaw was reported by Google’s Threat Analysis Group, presumably discovered in the wild, and the fix was pushed as stable on the 14th.

Then, on th 18th, yet another released rolled out to fix CVE-2023-2136, also reported by the TAG, also being exploited in the wild. It seems likely that both of these 0-days were found in the same exploitation campaign. We look forward to hearing the details on this one. Continue reading “This Week In Security: Spandex Tempest, Supply Chain Chain, And NTP” →

This Week In Security: QueueJumper, JS VM2 Escape, And CAN Hacking

April 14, 2023 by 9 Comments

You may not be familiar with the Microsoft Message Queuing (MSMQ) service, a store and forward sort of inter-process and inter-system communication service. MSMQ has become something of a legacy product, but is still available as an optional component in Windows. And in addition to other enterprise software solutions, Microsoft Exchange turns the service on by default. That’s why it’s a bit spooky that there’s a one packet Remote Code Execution (RCE) vulnerability that was just patched in the service.

CVE-2023-21554, also known as QueueJumper, is this unauthenticated RCE with a CVSS score of 9.8. It requires sending a packet to the service on TCP port 1801. The Check Point Research team scanned for listening MSMQ endpoints on the public Internet, and found approximately 360,000 of them. And no doubt far more are listening on internal networks. A one packet exploit is a prime example of a wormable problem, and now that the story has broken, and the patch is available, expect a rapid reverse engineering. Beware, the queue jumpers are coming.

JavaScript VM Escape

The VM2 library is a rather important JavaScript package that sandboxes code, letting a project run untrusted code securely. Or, that’s the idea. CVE-2023-29017 is an example of how hard sandboxing is to get right. It’s another CVSS 9.8 vulnerability, and this one allows a sandbox escape and code execution.

This one now has public Proof of Concept code, and this package has over 16 million monthly installs, so the attack surface is potentially pretty wide. The flaw is fixed in version 3.9.15. Continue reading “This Week In Security: QueueJumper, JS VM2 Escape, And CAN Hacking” →

This Week In Security: Cookie Monster, CyberGhost, NEXX, And Dead Angles

April 7, 2023 by 5 Comments

“Operation Cookie Monster” ranks as one of the best code names in recent memory. And it’s apropo, given what exactly went down. Genesis Market was one of those marketplaces where criminals could buy and sell stolen credentials. This one was a bit extra special.

Websites and services are getting better about detecting logins from unexpected computers. Your Google account suddenly logs in from a new computer, and a two-factor authentication challenge launches. Why? Your browser is missing a cookie indicating you’ve logged in before. But there’s more. Providers have started rolling out smart analytics that check for IP address changes and browser fingerprints. Your mix of time zone, user string, installed fonts, and selected language make a pretty unique identifier. So sites like Genesis offer Impersonation-as-a-Service (IMPaaS), which is session hijacking for the modern age.

A victim computer gets owned, and credentials are collected. But so are cookies and a browser fingerprint. Then a criminal buyer logs in, and runs a virtual browser with all that collected data. Run through a proxy to get a IP that is geolocated close enough to the victim, and Mr. Bad Guy has a cloned machine with all accounts intact.

And now back to Operation Cookie Monster, a multi-organization takedown of Genesis. It’s apparently a partial takedown, as the latest word is that the site is still online on the Tor network. But the conventional domains are down, and something like eight million credentials have been captured and added to the Have I Been Pwned database.

Another researcher team, Sector 7, has been working the case with Dutch authorities, and has some interesting details. The vector they cover was a fake activation crack for an antivirus product. Ironic. There are several extensions that get installed on the victim computer, and one of the most pernicious is disguised as Google Drive. This extension looks for a Command and Control server, using Bitcoin as DNS. A hardcoded Bitcoin address is polled for its latest transaction, and the receiving address is actually an encoded domain name, you-rabbit[.]com as of the latest check.

This extension will look for and rewrite emails that might be warning the victim about compromise. Get an email warning about a cryptocurrency withdrawal? It modifies it in the browser to be a sign-in warning. It also allows Genesis customers to proxy connections through the victim’s browser, bypassing IP address security measures. Continue reading “This Week In Security: Cookie Monster, CyberGhost, NEXX, And Dead Angles” →

This Week In Security: Macstealer, 3CX Carnage, And Github’s Lost Key

March 31, 2023 by 6 Comments

There’s a naming overload here, as two bits of security news this week are using the “MacStealer” moniker. We’re first going to talk about the WiFi vulnerability, also known as Framing Frames (pdf). The WPA encryption schemes introduced pairwise encryption, ensuring that not even other authenticated users can sniff each others’ traffic. At least that’s the idea, but this attack finds a couple techniques to bypass that protection.

A bit more background, there are a couple ways that packets can be delayed at the sender side. One of those is the power-save message, that signals the access point that the given client is going into a low power state. “Hold my calls, I’m going to sleep.” That message is a single bit in a frame header. And notably, that bit isn’t covered by WPA encryption or verification. An attacker can send a message, spoof a victim’s MAC address, and the access point marks that client as being in power-save mode.

This observation leads to a question: What happens when the encryption details change between the packet joining the queue, and actually transmitting? Turns out, the specifications on WiFi encryption don’t spell it out, and some implementations do the last thing you’d want, like sending the packets in the clear. Whoops. This behavior was the case in the Linux kernel through version 5.5.0, but starting with 5.6.0, the buffered packets were simply dropped when the encryption key was unavailable. Continue reading “This Week In Security: Macstealer, 3CX Carnage, And Github’s Lost Key” →