openssh

5 Articles

This Week In Security: Dating App, WooCommerce, And OpenSSH

July 21, 2023 by 4 Comments

Up first this week is a report from vpnMentor, covering the unsecured database backing a set of dating apps, including 419 Dating. The report is a bit light on the technical details, like what sort of database this was, or how exactly it was accessed. But the result is 2.3 million exposed records, containing email address, photos — sometimes explicit, and more. Apparently also exposed were server backups and logs.

The good news here is that once [Jeremiah Fowler] discovered the database door unlocked and hanging open, he made a disclosure, and the database was secured. We can only hope that it wasn’t discovered by any bad actors in the meantime. The app has now disappeared from the Google Play store, and had just a bit of a sketchy air about it.

WooCommerce Under Siege

Back in March, CVE-2023-28121 was fixed in the WooCommerce plugin for WordPress. The issue here is an authentication bypass that allows an unauthenticated user to commandeer other user accounts.

Within a few months, working exploits had been derived from the details of the patch plugging the hole. It wasn’t hard. A function for determining the current user was explicitly trusting the contents of the X-WCPAY-PLATFORM-CHECKOUT-USER request header. Set that value in a request sent to the server, and ding, you’re administrator.

And now the cows are coming home to roost. Active exploitation started in earnest on July 14, and the folks at Wordfence clocked a staggering 1.3 million exploitation attempts on the 16th. What’s particularly interesting is that the Wordfence data gathering system saw a huge increase in requests for the readme.txt file that indicates the presence of the WooCommerce plugin on a WordPress site. These requests were observed before the attacks got started, making for an interesting early warning system. Continue reading “This Week In Security: Dating App, WooCommerce, And OpenSSH” →

SSH Can Handle Spaces In Command-line Arguments Strangely

July 15, 2023 by 48 Comments

One of the things ssh can do is execute a command on a remote server. Most of us expect it to work transparently when doing so, simply passing the command and its arguments on without any surprises in the process. But after 23 years of using OpenSSH on a nearly daily basis, [Martin Kjellstrand] got surprised.

It turns out that the usual rules around how things are parsed can have some troublesome edge cases when spaces are involved. [Martin] kicks off an example in the following way:

One would reasonably expect the commands figlet foobar bar\ baz and ssh localhost figlet foobar bar\ baz to be functionally equivalent, right? The former ultimately runs the command “figlet” with arguments “foobar” and “bar baz” on the local machine. The second does the same, except with ssh being involved in the middle. As mentioned, one would expect both commands to be functionally identical, but that’s not what happens. What happens is that ssh turns bar\ baz into two distinctly separate command-line arguments in the process of sending it for remote execution: “bar” and “baz”. The result is mystification as the command fails to run the way the user expects, if it runs at all.

What exactly is going on, here? [Martin] goes into considerable detail tracking down this odd behavior and how it happens, but he’s unable to ultimately explain why ssh does things this way. He suspects that it is the result of some design decision taken long ago. Or perhaps a bug that has, over time, been promoted to entrenched quirk.

Do you have any insights or knowledge about this behavior? If so, [Martin] wants to hear about it and so do we, so don’t keep it to yourself! Let us know in the comments, below.

This Week In Security: DNSSEC Temporarily Lost Their Keys, FIDO, And One Weird Windows Trick

February 21, 2020 by 12 Comments

DNSSEC is the system that allows for cryptographically secure DNS. It’s all based on a root cryptographic key, maintained by the Internet Assigned Numbers Authority (IANA). Ever wondered where the root Key Signing Key is stored, and how it’s accessed? Four times a year, a ceremony is held where the root key is pulled out of a physical safe, and maintenance tasks are performed in front of a group of witnesses.

Such an event was scheduled for February 12th, but a teensy problem was discovered. One of the safes that holds the key media had a broken lock, and the root key signing key was inaccessible for a few days while repairs were effected. The open nature of IANA means that much of their operations are publicly reported, and you can even watch the key signing ceremony, which was finally held on February 16th.

Continue reading “This Week In Security: DNSSEC Temporarily Lost Their Keys, FIDO, And One Weird Windows Trick” →

This Week In Security: Invalid Curve Attacks, OpenSSH Shielded, And More Details On Coinbase

June 28, 2019 by 19 Comments

AMD Epyc processors support Secure Encrypted Virtualization (SEV), a technique that prevents even a hypervisor reading memory belonging to a virtual machine. To pull this off, the encryption and decryption is handled on the fly by the Platform Security Processor (PSP), which is an ARM core that handles processor start-up and many security features of modern AMD processors. The vulnerability announced this week is related to the encryption scheme used. The full vulnerability is math heavy, and really grokking it requires a deeper understanding of elliptical curve cryptography (ECC) than your humble author currently possesses.

During the process of starting a virtual machine, the VM process goes through a key-sharing process with the PSP, using an ECC Diffie-Hellman key exchange. Rather than raising prime numbers to prime exponents, an ECC-DH process bounces around inside an elliptical curve in order to find a shared secret. One of the harder problems to solve when designing an ECC based cryptographic system, is the design of the curve itself. One solution to this problem is to use a published curve that is known to be good. AMD has taken this route in their SEV feature.

The attack is to prime the key exchange with invalid data, and observing the shared key that is generated. A suitably simple initial value will leak information about the PSP’s secret key, allowing an attacker to eventually deduce that key and decrypt the protected memory. If you’d like to bone up on invalid curve attacks, here’s the seminal paper. (PDF)

OpenSSH Shielding

[Damien Miller] of OpenSSH was apparently tired of seeing that project tied to vulnerabilities like Rambleed and Rowhammer, so added a technique he’s calling key-shielding. OpenSSH now encrypts private keys in memory using a 16 kB pre-key. While an attacker with full knowledge of the process’s memory wouldn’t be deterred, the error rate of Rambleed and similar attacks is high enough that the 16 kB of randomness is likely to thwart the attempt to recover the secret key.

Firefox and Coinbase

We mentioned Firefox vulnerabilities and updates last week, and as anticipated, more information is available. [Philip Martin] from Coinbase shared more information on Twitter. Coinbase employees, as well as other cryptocurrency companies, were targeted with fishing emails. These lured employees to a malicious page that attempted to exploit a pair of Firefox vulnerabilities. Coinbase has a security system in place that was able to prevent the exploit, and their security team was able to reverse engineer the attack.

The first vulnerability has been dissected in some detail by a Google security researcher. It’s a weakness in Firefox’s Javascript engine related to type handling. An object is created with one data type, and when that data is changed to another type, not all the data handlers are appropriately updated. Under the hood, a value is assumed to be a pointer, but is actually a double-length value, controlled by the attacker.

The second vulnerability is in the functions used to prompt for user interaction. Specifically the call to “Prompt:Open” isn’t properly validated, and can result in the un-sandboxed Firefox process loading an arbitrary web location. I suspect the sandbox escape is used to run the initial exploit a second time, but this time it’s running outside the sandbox.

Odds and Ends

[Tom] wrote a great intro into how to Impersonate The President With Consumer-Grade SDR, go check it out!

Another city, more ransomware. Riviera Beach, Florida was hit with a ransomware attack, and paid $600,000 in an attempt to get their data back. For a city of 35,000 inhabitants, that’s $17.14 in ransom per man, woman, and child. According to the linked article, though, the city was insured.

Red Hat Confirms Security Breach

August 23, 2008 by 2 Comments


After a week of wondering, Red Hat has confirmed that someone broke in and compromised their security. Although It doesn’t appear the attacker was able to retrieve the passphrase used to sign Fedora packages, the team is switching to new keys. In a separate intrusion the attacker tampered with and signed OpenSSH packages for RHEL. While it’s good to get the full story, no one is happy how long it took Red Hat to release these details.

[via Zero Day]

[photo: afsilva]