Windows update

New year, new vulnerabilities

This blog post is a summary of this week’s Information Security News put together by our Security Incident Response Team (SIRT).

The year 2020 started of by throwing out a bunch of new vulnerabilities that needed fixing.
First it was the Citrix vulnerability in Application Delivery Controller and Gateway products, formerly known as netscaler. The vulnerability was technically was released in 2019 as CVE-2019-19781; and allowed an attacker to get arbitrary remote code execution trough a directory traversal. The exploit was really easy to pull of and only needed two web-requests to the gateway, and multiple POC was released early January leading to active exploitation in the wild. Citrix has not yet released a patch for the vulnerability, but instead released a way to mitigate the vulnerability by means of configuration. A patch is expected next week.

Then on Tuesday, 14th of January Microsoft released its monthly patches fixing a bunch of bugs and security issues. In this patch there were two critical vulnerabilities that warranted extra atention. One was dubbed “curveball” and is tracked as CVE-2020-0601. Curveball is a bug in the Windows crypto API(Crypt32.dll) and how Windows Elliptic Curve Cryptography (ECC). The vulnerability allows anyone to present a certificate, and windows will happily acknowledge it as a valid certificate even when it is no. This could let an attacker launch Man-in-the-middle attacks against HTTPS connections, present fake certificates for phishing pages and allow fake signed executables to be launched. The vulnerability affects Windows 10, and Windows server 20016 and later.

Another big one from this patch was the Microsoft RD gateway vulnerability tracked as CVE-2020-0609 allowing arbitrary remote code execution by sending a specially crafted request to the server over the RDP connection. By using this exploit an attacker could get full access to the server by means of installing software, create users with full access rights etc.

There were also multiple other other vulnerabilities fixed, such as CVE-2020-0603 is a critical remote code execution bug in ASP.NET Core allowing an attacker to execute code by getting a user to open a file, and CVE-2020-0636 (Windows Subsystem for Linux (WSL)) allowing a user to run commands with elevated privileges.

In other news, SHA-1 is a Shambles after the first chosen prefix collision for sha1 was done. This means that sha1 is considered unsafe to use for integrity checking as you can create two documents that are completely different, add extra data to make them the same length and then add some specific data to generate the same sha1-sum for both documents. SHA1 should now be avoided for integrity checking of data.

A total of 334 vulnerabilities was patched by Oracle this week, covering many widely used applications like MySQL, VirtualBox, Java and Oracle Database.

On a different note, Windows 7 and windows server 2008(r2) is now end of life as of January 14, and will not get any more security updates. Microsoft wil also up the fees for running these operation systems, so both from a economical and security standpoint it makes sense to upgrade now sooner than later.

To sum up this weeks security news, stay up to date with patching at all times. There is no excuse not to.