Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

ABTV

12/6/2019
11:00 AM
Larry Loeb
Larry Loeb
Larry Loeb
50%
50%

Zero-Day Vulnerabilities Discovered in Enterprise-Grade VPN

Aviatrix, an enterprise VPN company with customers that include NASA, Shell and BT, has recently dealt with a vulnerability that was uncovered by Immersive Labs researcher and content engineer Alex Seymour.

Aviatrix, an enterprise VPN company with customers that include NASA, Shell and BT, has recently dealt with a vulnerability that was uncovered by Immersive Labs researcher and content engineer Alex Seymour. The descriptive blog was releasedon December 5, 2019 and outlines the specifics of the problem.

Seymour says in it that, "The vulnerability would have allowed an attacker who already had access to a machine to escalate privileges and achieve anything they wanted; for example, gaining access to files, folders and network services that the user would not previously have been able to access."

Multiple local privilege escalation vulnerabilities were discovered in the Aviatrix VPN client. On each operating system there are two main parts to the VPN client. This first is a service enabled by default post-installation, as well as the user-client application that interfaces between the user and the services.

One vulnerability is "Privilege Escalation Through Weak File Permissions" (CVE-2019-17388). Seymour found that during the VPN's installation process on Windows, Linux and FreeBSD, the permission set applied to the client's installation directory was highly permissive. The Linux, macOS and FreeBSD versions of the VPN client use the openvpn command's --up and --down flags to execute shell scripts when a VPN connection is established and terminated respectively.

Now, because of the weak file permissions that are set on the installation directory on Linux and FreeBSD, it is possible to modify these scripts. As the backend service executes the openvpn command, this can result in the script being executed with elevated privileges.

This reveal comes two months after the National Security Agency (NSA) and National Security Council (NSC) warned of state-sponsored attackers that were targeting vulnerabilities in VPNs.

Seymour noted that, "Coming hot on the heels of the UK and US Government warnings about VPN vulnerabilities, this underlines that often the technology protecting enterprises needs to be managed as tightly as the people using it. People tend to think of their VPN as one of the more secure elements of their security posture, so it should be a bit of a wakeup call for the industry."

Seymour also found a "Privilege Escalation via Service Code Execution" (CVE-2019-17387) vulnerability. The service uses certificate authentication to validate that requests stem from a valid source, which is hoped to prevent anyone except the client application from making requests to the service. But when the application is running, the needed certificates for code execution of a file can be recovered from the operating system's temporary directory; the filename is prefixed with mvLOKecsEpki. It is possible to craft requests to the service and gain code execution by passing commands wrapped in subshells in args instead of the expected file paths.

A patch for the VPN has been released (v2.4.10) and can be found at https://docs.aviatrix.com/Downloads/samlclient.html#aviatrix-vpn-client.

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Cloud Security Threats for 2021
Or Azarzar, CTO & Co-Founder of Lightspin,  12/3/2020
Why Vulnerable Code Is Shipped Knowingly
Chris Eng, Chief Research Officer, Veracode,  11/30/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win an Amazon Gift Card! Click Here
Latest Comment: This comment is waiting for review by our moderators.
Current Issue
2021 Top Enterprise IT Trends
We've identified the key trends that are poised to impact the IT landscape in 2021. Find out why they're important and how they will affect you today!
Flash Poll
Assessing Cybersecurity Risk in Todays Enterprises
Assessing Cybersecurity Risk in Todays Enterprises
COVID-19 has created a new IT paradigm in the enterprise and a new level of cybersecurity risk. This report offers a look at how enterprises are assessing and managing cyber-risk under the new normal.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-27772
PUBLISHED: 2020-12-04
A flaw was found in ImageMagick in coders/bmp.c. An attacker who submits a crafted file that is processed by ImageMagick could trigger undefined behavior in the form of values outside the range of type `unsigned int`. This would most likely lead to an impact to application availability, but could po...
CVE-2020-27773
PUBLISHED: 2020-12-04
A flaw was found in ImageMagick in MagickCore/gem-private.h. An attacker who submits a crafted file that is processed by ImageMagick could trigger undefined behavior in the form of values outside the range of type `unsigned char` or division by zero. This would most likely lead to an impact to appli...
CVE-2020-28950
PUBLISHED: 2020-12-04
The installer of Kaspersky Anti-Ransomware Tool (KART) prior to KART 4.0 Patch C was vulnerable to a DLL hijacking attack that allowed an attacker to elevate privileges during installation process.
CVE-2020-27774
PUBLISHED: 2020-12-04
A flaw was found in ImageMagick in MagickCore/statistic.c. An attacker who submits a crafted file that is processed by ImageMagick could trigger undefined behavior in the form of a too large shift for 64-bit type `ssize_t`. This would most likely lead to an impact to application availability, but co...
CVE-2020-27775
PUBLISHED: 2020-12-04
A flaw was found in ImageMagick in MagickCore/quantum.h. An attacker who submits a crafted file that is processed by ImageMagick could trigger undefined behavior in the form of values outside the range of type unsigned char. This would most likely lead to an impact to application availability, but c...