This Week in Security

254 Articles

This Week In Security: NAME:WRECK, Signal Hacks Back, Updates, And More

April 23, 2021 by 9 Comments

NAME:WRECK is a collection of vulnerabilities in DNS implementations, discovered by Forescout and JSOF Research. This body of research can be seen as a continuation of Ripple20 and AMNESIA:33, as it builds on a class of vulnerability discovered in other network stacks, problems with DNS message compression.

Their PDF Whitepaper contains a brief primer on the DNS message format, which is useful for understanding the class of problem. In such a message, a DNS name is encoded with a length-value scheme, with each full name ending in a null byte. So in a DNS Request, Hackaday.com would get represented as [0x08]Hackaday[0x03]com[0x00]. The dots get replaced by these length values, and it makes for an easily parsable format.

Very early on, it was decided that continually repeating the same host names in a DNS message was wasteful of space, so a compression scheme was devised. DNS compression takes advantage of the maximum host/domain length of 63 characters. This max size means that the binary representation of that length value will never contain “1”s in the first two digits. Since it can never be used, length values starting with a binary “11” are used to point to a previously occurring domain name. The 14 bits that follow this two bit flag are known as a compression pointer, and represent a byte offset from the beginning of the message. The DNS message parser pulls the intended value from that location, and then continues parsing.

The problems found were generally based around improper validation. For example, the NetX stack doesn’t check whether the compression pointer points at itself. This scenario leads to a tight infinite loop, a classic DoS attack. Other systems don’t properly validate the location being referenced, leading to data copy past the allocated buffer, leading to remote code execution (RCE). FreeBSD has this issue, but because it’s tied to DHCP packets, the vulnerability can only be exploited by a device on the local network. While looking for message compression issues, they also found a handful of vulnerabilities in DNS response parsing that aren’t directly related to compression. The most notable here being an RCE in Seimens’ Nucleus Net stack. Continue reading “This Week In Security: NAME:WRECK, Signal Hacks Back, Updates, And More” →

This Week In Security: Pwn2own, Zoom Zero Day, Clubhouse Data, And An FBI Hacking Spree

April 16, 2021 by 11 Comments

Our first story this week comes courtesy of the Pwn2own contest. For anyone not familiar with it, this event is held twice a year, and features live demonstrations of exploits against up-to-date software. The one exception to this is when a researcher does a coordinated release with the vendor, and the update containing the fix drops just before the event. This time, the event was held virtually, and the attempts are all available on Youtube. There were 23 attacks attempted, and only two were outright failures. There were 5 partial successes and 16 full successes.

One of the interesting demonstrations was a zero-click RCE against Zoom. This was a trio of vulnerabilities chained into a single attack. The only caveat is that the attack must come from an accepted contact. Pwn2Own gives each exploit attempt twenty minutes total, and up to three attempts, each of which can last up to five minutes. Most complex exploits have an element of randomness, and exploits known to work sometimes don’t work every time. The Zoom demonstration didn’t work the first time, and the demonstration team took enough time to reset, they only had enough time for one more try.

BleedingTooth

We first covered BleedingTooth almost exactly six months ago. The details were sparse then, but enough time has gone by to get the full report. BleedingTooth is actually a trio of vulnerabilities, discovered by [Andy Nguyen]. The first is BadVibes, CVE-2020-24490. It’s a lack of a length check in the handling of incoming Bluetooth advertisement packets. This leads to a buffer overflow. The catch here is that the vulnerability is only possible over Bluetooth 5. Continue reading “This Week In Security: Pwn2own, Zoom Zero Day, Clubhouse Data, And An FBI Hacking Spree” →

This Week In Security: The Facebook Leak, The YouTube Leak, And File Type Confusion

April 9, 2021 by 21 Comments

Facebook had a problem, way back in the simpler times that was 2019. Something like 533 million accounts had the cell phone number associated with the account leaked. It’s making security news this week, because that database has now been released for free in its entirety. The dataset consists of Facebook ID, cell number, name, location, birthday, bio, and email address. Facebook has pointed out that the data was not a hack or breach, but was simply scraped prior to a vulnerability being fixed in 2019.

The vulnerability was in Facebook’s contact import service, also known as the “Find Friends” feature. The short explanation is that anyone could punch a random phone number in, and get a bit of information about the FB account that claimed that number. The problem was that some interfaces to that service didn’t have appropriate rate limiting features. Combine that with Facebook’s constant urging that everyone link a cell number to their account, and the default privacy setting that lets anyone locate you by your cell number, and the data scraping was all but inevitable. The actual technique used may have been to spoof that requests were coming from the official Facebook app.

[Troy Hunt]’s Have i been pwned service has integrated this breach, and now allows searching by phone number, so go check to see if you’re one of the exposed. If you are, keep the leaked data in mind every time an email or phone call comes from someone you don’t know. Continue reading “This Week In Security: The Facebook Leak, The YouTube Leak, And File Type Confusion” →

This Week In Security: Ubiquity Update, PHP Backdoor, And Netmask

April 2, 2021 by 11 Comments

Back in January, we covered the news that Ubiquiti had a breach of undisclosed severity. One reader pointed out the compromise of a handful of devices as potentially related. With no similar reports out there, I didn’t think too much of it at the time. Now, however, a whistleblower from Ubiquiti has given Krebs the juicy details.

The “third party cloud provider” the original disclosure referred to was Amazon Web Services (AWS). According to the whistleblower, just about everything was accessible, including the keys to log in to any Ubiquiti device on the internet, so long as it was cloud enabled. The attackers installed a couple of backdoors in Ubiquiti’s infrastructure, and sent a 50 bitcoin blackmail threat. To their credit, Ubiquiti ignored the blackmail and cleaned up the mess.

To the claim that there was no evidence attackers had accessed user accounts, it seems that the database in question simply has no logging enabled. There was no evidence, because nothing was watching. So far, I’ve only seen the one report of device compromise that was potentially a result of the attack. If you had a Ubiquiti device go rogue around December 2020 – January 2021, be sure to let us know. Continue reading “This Week In Security: Ubiquity Update, PHP Backdoor, And Netmask” →

This Week In Security: XcodeSpy, Insecure SMS, And Partial Redactions

March 26, 2021 by 25 Comments

There seems to be a new trend in malware, targeting developers and their development and build processes. The appeal is obvious: rather than working to build and market a malicious application, an attacker just needs to infect a development machine. The hapless infected developers can now do the hard work to spread the malicious payload.

The newest example is XcodeSpy, discovered by a researcher who chose to remain anonymous. It works by using the Xcode IDE’s Run Script function to, well, run a script that completely backdoors your computer. The instance was found in a repackaged open source project, TabBarInteraction, but they’re just innocent victims. It was simple enough for someone to insert a script in the build process, and distribute the new, doped package. It’s probably not the only one out there, so watch out for Run Scripts with obfuscated payloads.

Continue reading “This Week In Security: XcodeSpy, Insecure SMS, And Partial Redactions” →

This Week In Security: Spectre In The Browser, Be Careful What You Clone, And Hackintosh

March 19, 2021 by 12 Comments

Google has been working on mitigations for the Spectre attack, and has made available a Proof of Concept that you can run in your browser right now. Spectre is one of the issues that kicked off the entire series of speculative execution vulnerabilities and fixes. What Google has demonstrated is that the Spectre attack can actually be pulled off in Javascript, right in the browser. Spectre is limited to reading memory allocated to the same process, and modern browsers have implemented measures like site isolation, which puts each site in a separate, sandboxed process.

These security features don’t mean that there is no practical dangers from Spectre. There are a handful of ways an attacker can run Javascript on another site, from something as simple as an interactive advertisement, to a cross-site scripting injection. Google has produced features and guidance to mitigate those dangers.

Via Bleeping Computer. Continue reading “This Week In Security: Spectre In The Browser, Be Careful What You Clone, And Hackintosh” →

This Week In Security: Text Rendering On Windows, GNU Poke, And Bitsquatting

March 5, 2021 by 27 Comments

Project Zero just unrestricted the details on CVE-2021-24093, a potentially nasty vulnerability in Windows 10’s DirectWrite, a text rendering library. The flaw got fixed in this month’s patch Tuesday roundup. The flaw is accessible in all the major browsers on Windows 10, as they use DirectWrite for font rendering. The trick here is to use a malicious font that uses some nonsense values. Those values result in a buffer allocation that is too small for complex characters such as Æ.

Because the vulnerability is a Windows library, it’s possible that an exploit would automatically work as a sandbox escape, but I haven’t seen confirmation either way. Let us know if you have some insight there.

Via Bleeping Computer

GNU Poke

The good folks at GNU have minted the 1.0 release of poke, a new binary editing tool. The real killer feature of poke is that it can interpret binary data, decoding it back into readable data structures. If you’re familiar with the way Wireshark can decode packets and give useful, organized output, it seems that poke will provide a similar function, but not limited to network traffic.

It looks like it could become a useful tool for getting a look inside otherwise opaque binaries. What poke brings is a system where you can write pretty-printing templates on the fly, which should be very useful when mapping out an unfamiliar binary. Distros will likely pick up and start packaging poke in the coming weeks, making it even easier to get and play with. Continue reading “This Week In Security: Text Rendering On Windows, GNU Poke, And Bitsquatting” →