This Week in Security

291 Articles

This Week In Security: OpenOffice Vulnerable, IOS Vulnerable, Outlook… You Get The Idea

October 1, 2021 by 13 Comments

We start this week with a good write-up by [Eugene Lim] on getting started on vulnerability hunting, and news of a problem in OpenOffice’s handling of DBase files. [Lim] decided to concentrate on a file format, and picked the venerable dbase format, .dbf. This database format was eventually used all over the place, and is still supported in Microsoft Office, Libreoffice, and OpenOffice. He put together a fuzzing approach using Peach Fuzzer, and found a handful of possible vulnerabilities in the file format, by testing a very simple file viewer that supported the format. He managed to achieve code execution in dbfview, but that wasn’t enough.

Armed with a vulnerability in one application, [Lim] turned his attention to OpenOffice. He knew exactly what he was looking for, and found vulnerable code right away. A buffer is allocated based on the specified data type, but data is copied into this buffer with a different length, also specified in the dbase file. Simple buffer overflow. Turning this into an actual RCE exploit took a bit of doing, but is possible. The disclosure didn’t include a full PoC, but will likely be reverse engineered shortly.

Normally we’d wrap by telling you to go get the update, but OpenOffice doesn’t have a stable release with this fix in it. There is a release candidate that does contain the fix, but every stable install of OpenOffice in the world is currently vulnerable to this RCE. The vulnerability report was sent way back on May 4th, over 90 days before full disclosure. And what about LibreOffice, the fork of OpenOffice? Surely it is also vulnerable? Nope. LibreOffice fixed this in routine code maintenance back in 2014. The truth of the matter is that when the two projects forked, the programmers who really understood the codebase went to LibreOffice, and OpenOffice has had a severe programmer shortage ever since. I’ve said it before: Use LibreOffice, OpenOffice is known to be unsafe. Continue reading “This Week In Security: OpenOffice Vulnerable, IOS Vulnerable, Outlook… You Get The Idea” →

This Week In Security: Somebody’s Watching, Microsoft + Linux, DDoS

September 24, 2021 by 23 Comments

In case you needed yet another example of why your IoT devices shouldn’t be exposed to the internet, a large swath of Hikvision IP Cameras have a serious RCE vulnerability. CVE-2021-36260 was discovered by the firm Watchful_IP in the UK. In Hikvision’s disclosure, they refer to the problem as a command injection vulnerability in the device’s web interface. The vuln is pre-authentication, and requires no user interaction. This could be something as simple as a language chooser not sanitizing the inputs on the back-end, and being able to use backticks or a semicolon to trigger an arbitrary command.

Now you’re probably thinking, “I don’t use Hikvision cameras.” The sneaky truth is that a bunch of cameras with different brand names are actually Hikvision hardware, with their firmware based on the Hikvision SDK. The outstanding question about this particular vulnerability is whether it’s present in any of the re-labelled cameras. Since the exact vulnerability has yet to be disclosed, it’s hard to know for sure whether the relabeled units are vulnerable.  But if we were betting… Continue reading “This Week In Security: Somebody’s Watching, Microsoft + Linux, DDoS” →

This Week In Security: Office 0-day, ForcedEntry, ProtonMail, And OMIGOD

September 17, 2021 by 10 Comments

A particularly nasty 0-day was discovered in the wild, CVE-2021-40444, a flaw in how Microsoft’s MSHTML engine handled Office documents. Not all of the details are clear yet, but the result is that opening a office document can trigger a remote code execution. It gets worse, though, because the exploit can work when simply previewing a file in Explorer, making this a potential 0-click exploit. So far the attack has been used against specific targets, but a POC has been published.

It appears that there are multiple tricks that should be discrete CVEs behind the exploit. First, a simple invocation of mshtml:http in an Office document triggers the download and processing of that URL via the Trident engine, AKA our old friend IE. The real juicy problem is that in Trident, an iframe can be constructed with a .cpl URI pointing at an inf or dll file, and that gets executed without any prompt. This is demonstrated here by [Will Dormann]. A patch was included with this month’s roundup of fixes for Patch Tuesday, so make sure to update. Continue reading “This Week In Security: Office 0-day, ForcedEntry, ProtonMail, And OMIGOD” →

This Week In Security: Ghoscript In Imagemagick, Solarwinds, And DHCP Shenanigans

September 10, 2021 by 3 Comments

A PoC was just published for a potentially serious flaw in the Ghostscript interpreter. Ghostscript can load Postscript, PDF, and SVG, and it has a feature from Postscript that has been a continual security issue: the %pipe% command. This command requests the interpreter to spawn a new process — It’s RCE as part of the spec. This is obviously a problem for untrusted images and documents, and Ghostscript has fixed security vulnerabilities around this mis-feature several times over the years.

This particular vulnerability was discovered by [Emil Lerner], and described at ZeroNights X. That talk is available, but in Russian. The issue seems to be a bypass of sorts, where the pipe command appears to be working in the /tmp/ directory, but a simple semicolon allows for an arbitrary command to be executed. Now why is this a big deal? Because ImageMagick uses Ghostscript to open SVG images by default on some distributions, and ImageMagick is often used for automatically resizing and converting images for web sites. In [Emil]’s presentation, he uses this flaw as part of an attack chain against three different companies.

I was unable to reproduce the flaw on my Fedora install, but I haven’t found any notice of it being fixed in the Ghostscript or Imagemagick changelogs either. It’s unclear if this problem has already been fixed, or if this is a true 0-day for some platforms. Either way, expect attackers to start trying to make use of it.

Continue reading “This Week In Security: Ghoscript In Imagemagick, Solarwinds, And DHCP Shenanigans” →

This Week In Security: Ransomware Decryption, OpenSSL, And USBGadget Spoofing

September 3, 2021 by 8 Comments

We’ve covered a lot of ransomware here, but we haven’t spent a lot of time looking at the decryptor tools available to victims. When ransomware gangs give up, or change names, some of them release a decryption tool for victims who haven’t paid. It’s not really a good idea to run one of those decryptors, though. The publishers don’t have a great track record for taking care of your data, after all. When a decryptor does get released, and is verified to work, security researchers will reverse engineer the tool, and release a known-good decryption program.

The good folks at No More Ransom are leading the charge, building such tools, and hosting a collection of them. They also offer Crypto Sheriff, a tool to identify which ransomware strain got your files. Upload a couple encrypted files, and it will inform you exactly what you’re dealing with, and whether there is a decryptor available. The site is a cooperation between the Dutch police, Interpol, Kaspersky, and McAfee. It may surprise you to know that they recommend reporting every ransomware case to the authorities. I can confirm that at the very least, the FBI in the US are very interested in keeping track of the various ransomware attacks — I’ve fielded a surprise call from an agent following up on an infection.

OpenSSL

The OpenSSL project has fixed a pair of vulnerabilities, CVE-2021-3711 and CVE-2021-3712 with release 1.1.11l. The first is a possible buffer overflow caused by a naive length calculation function. A “fixed” length header is actually dynamic, so a carefully crafted plaintext can overflow the allocated buffer. Continue reading “This Week In Security: Ransomware Decryption, OpenSSL, And USBGadget Spoofing” →

This Week In Security: Through The Mouse Hole, Zoom RCE, And Defeating Defender

August 27, 2021 by 9 Comments

Windows security problems due to insecure drivers is nothing new, but this one is kinda special. Plug in a Razer mouse, tell the install dialog you want to install to a non-standard location, and then shift+right click the Explorer window. Choose a powershell, and boom, you now have a SYSTEM shell. It’s not as impressive as an RCE, and it requires hands-on the machine, but it’s beautiful due to the simplicity of it.

The problem is a compound one. First, Windows 10 and 11 automatically downloads and starts the install of Razer Synapse when a Razer device is plugged in. Note it’s not just Razer, any branded app that auto installs like this is possibly vulnerable in the same way. The installation process runs as system, and because it was started automatically, there is no admin account required. The second half of the issue is that the installer itself doesn’t take any precautions to prevent a user from spawning additional processes. There isn’t an obvious way to prevent the launch of Powershell from within the FolderPicker class, so an installer running as SYSTEM would have to go out of its way to drop privileges, to make this a safe process. The real solution is for Microsoft to say no to GUI installers bundled with WHQL signed drivers.
Continue reading “This Week In Security: Through The Mouse Hole, Zoom RCE, And Defeating Defender” →

This Week In Security: Breaking Apple ID, Political Hacktivism, And Airtag Tracking

August 20, 2021 by 10 Comments

Have you ever thought about all the complexities of a Single Sign On (SSO) implementation? A lot of engineering effort has gone into hardened against cross-site attacks — you wouldn’t want every site you visit to be able to hijack your Google or Facebook account. At the same time, SSO is the useful ability to use your authentication on one service to authenticate with an unrelated site. Does SSO ever compromise that hardening? If mistakes are made, absolutely, as [Zemnmez] discovered while looking at the Apple ID SSO system.

Continue reading “This Week In Security: Breaking Apple ID, Political Hacktivism, And Airtag Tracking” →