This Week in Security

258 Articles

This Week In Security: Watering Hole Attackception, Ransomware Trick, And More Pipeline News

May 21, 2021 by 11 Comments

In what may be a first for watering hole attacks, we’ve now seen an attack that targeted watering holes, or at least water utilities. The way this was discovered is a bit bizarre — it was found by Dragos during an investigation into the February incident at Oldsmar, Florida. A Florida contractor that specializes in water treatment runs a WordPress site that hosted a data-gathering script. The very day that the Oldsmar facility was breached, someone from that location visited the compromised website.

You probably immediately think, as the investigators did, that the visit to the website must be related to the compromise of the Oldsmar treatment plant. The timing is too suspect for it to be a coincidence, right? That’s the thing, the compromised site was only gathering browser fingerprints, seemingly later used to disguise a botnet. The attack itself was likely carried out over Teamviewer. I will note that the primary sources on this story have named Teamviewer, but call it unconfirmed. Assuming that the breach did indeed occur over that platform, then it’s very unlikely that the website visit was a factor, which is what Dragos concluded. On the other hand, it’s easy enough to imagine a scenario where the recorded IP address from the visit led to a port scan and the discovery of a VNC or remote desktop port left open. Continue reading “This Week In Security: Watering Hole Attackception, Ransomware Trick, And More Pipeline News” →

This Week In Security: Fragattacks, The Pipeline, Codecov, And IPv6

May 14, 2021 by 26 Comments

Some weeks are slow, and the picking are slim when discussing the latest security news. This was not one of those weeks.

First up is Fragattacks, a set of flaws in wireless security protocols, allowing unauthenticated devices to inject packets into the network, and in some cases, read data back out. The flaws revolve around 802.11’s support for packet aggregation and frame fragmentation. The whitepaper is out, so let’s take a look.

Fragmentation and aggregation are techniques for optimizing wireless connections. Packet aggregation is the inclusion of multiple IP packets in a single wireless frame. When a device is sending many small packets, it’s more efficient to send them all at once, in a single wireless frame. On the other hand, if the wireless signal-to-noise ratio is less than ideal, shorter frames are more likely to arrive intact. To better operate in such an environment, long frames can be split into fragments, and recombined upon receipt.

There are a trio of vulnerabilities that are built-in to the wireless protocols themselves. First up is CVE-2020-24588, the aggregation attack. To put this simply, the aggregation section of a wireless frame header is unauthenticated and unencrypted. How to exploit this weakness isn’t immediately obvious, but the authors have done something clever.

First, for the purposes of explanation, we will assume that there is already a TCP connection established between the victim and an attacker controlled server. This could be as simple as an advertisement being displayed on a visited web page, or an image linked to in an email. We will also assume that the attacker is performing a Man in the Middle attack on the target’s wireless connection. Without the password, this only allows the attacker to pass the wireless frames back and forth unmodified, except for the aggregation header data, as mentioned. The actual attack is to send a special IP packet in the established TCP connection, and then modify the header data on the wireless frame that contains that packet.

When the victim tries to unpack what it believes to be an aggregated frame, the TCP payload is interpreted as a discrete packet, which can be addressed to any IP and port the attacker chooses. To put it more simply, it’s a packet within a packet, and the frame aggregation header is abused to pop the internal packet out onto the protected network. Continue reading “This Week In Security: Fragattacks, The Pipeline, Codecov, And IPv6” →

This Week In Security: BYOVD, Spectre Vx, More Octal Headaches, And ExifTool

May 7, 2021 by 16 Comments

I learned a new acronym while reading about a set of flaws in the Dell BIOS update system. Because Dell has patched their driver, but hasn’t yet revoked the signing keys from the previous driver version, it is open to a BYOVD attack.

BYOVD, Bring Your Own Vulnerable Driver, is an interesting approach to Windows privilege escalation. 64-bit versions of Windows have a security feature that blocks unsigned kernel drivers from the kernel. The exploit is to load an older, known-vulnerable driver that still has valid signatures into the kernel, and use the old vulnerabilities to exploit the system. The caveat is that even when a driver is signed, it still takes an admin account to load a driver. So what use is the BYOVD attack, when it takes administrative access to pull off?

SentinelLabs is witholding their proof-of-concept, but we can speculate. The particular vulnerable driver module lives in the filesystem at C:\Windows\Temp, a location that is writable by any process. The likely attack is to overwrite the driver on the filesystem, then trigger a reboot to load the older vulnerable version. If you’re still running Windows on your Dell machines, then make sure to go tend to this issue. Continue reading “This Week In Security: BYOVD, Spectre Vx, More Octal Headaches, And ExifTool” →

This Week In Security: Dan Kaminsky, Banned From Kernel Development, Ransomware, And The Pentagon’s IPv4 Addresses

April 30, 2021 by 22 Comments

This week we’re starting off with a somber note, as Dan Kaminsky passed at only 42, of diabetic ketoacidosis. Dan made a name for himself by noticing a weakness in DNS response verification that could allow attackers to poison a target DNS resolver’s cache. A theoretical attack was known, where spoofed DNS responses could collide with requests, but Time-To-Live values meant that DNS requests only go out once per eight hours or so. The breakthrough was realizing that the TTL limitation could be bypassed by requesting bogus subdomains, and aiming the spoofed responses at those requests. This simple technique transformed a theoretical attack that would take 87 years to a very real 10 second attack. Check out the period video after the break, where Dan talked about his efforts in getting the problem fixed.
Continue reading “This Week In Security: Dan Kaminsky, Banned From Kernel Development, Ransomware, And The Pentagon’s IPv4 Addresses” →

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” →