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.

Vulnerabilities / Threats

Docker Vulnerability Opens Servers to Container Code

Under very specific conditions, code running in a Docker container could access files anywhere on a server, according to a new CVE.

A recently discovered vulnerability in the Docker container platform could allow an attacker to gain access to files used by other containers and the host server itself. And, in an unusual progression of events, the vulnerability and exploits have been disclosed before patches are available.

The vulnerability, designated CVE-2018-15664, was discovered by researcher Aleka Sarai. A flaw in the Docker "cp" command, which provides a method for copying a file from the host system to a container, could give an attacker arbitrary read-write access to the host file system with root privileges.

A "race condition" — specifically a "time of check to time of use" (TOCTOU) bug — lies at the heart of the vulnerability. In this case, the problem is that a file path that has been checked for safe and authorized copying conditions can be changed between the time of verification and the time of copying, changed to any file, anywhere on the host server.

"It's not just a violation of integrity and confidentiality. If the attacker successfully exploits this bug, not only can they get read and write access on data within the container, it actually opens the host itself to integrity and confidentiality violations as if it were in the container," says Kelly Shortridge, vice president of product strategy at Capsule8.

Fortunately, this is not a vulnerability that can be remotely exploited. "You'd have to own a container running on the server and then be able to control the code running in the container," explains Jerry Gamblin, principal security engineer at Kenna Security. And even within those containers, only the "cp" command is vulnerable.

That difficulty in exploiting the vulnerability is likely why the researchers and Docker community felt comfortable disclosing the vulnerability before a patch is available.

"The thing that grabbed me and was the talk of the security community yesterday is that they talked to people and allowed them to release the bug and the scripts before the patch was out, which to me indicates that it is probably low risk to most people," Gamblin says.

Until that patch is released, a brute-force fix may be the only remediation option.

"Because Docker 'cp' doesn't seem to be used in many automated processes, organizations for now can probably just block that utility until there's a fix out," Shortridge says.

In the hierarchy of things for a CISO to worry about, this vulnerability should be at a low level, both Gamblin and Shortridge say. Unfortunately, each also says there are factors that will keep it a low-level concern for some time to come.

"People should also be aware that it appears that Kubernetes is able to use Docker 'cp' as well," says Shortridge, which makes it possible for orchestration playbooks to include the vulnerability. And the vulnerability patch, when it arrives, may not make the problem go away.

The common practice of simply pulling an existing container from a Docker pool and using it means that, if the individual maintaining the container doesn't update it, developers pulling the vulnerable container might never know they are deploying a flawed container, Gamblin says.

Still, he points out, this is a weakness, but not a structural weakness. Shortridge agrees, saying this is a cause for caution, but not at all a reason for panic.

Related content:

Curtis Franklin Jr. is Senior Editor at Dark Reading. In this role he focuses on product and technology coverage for the publication. In addition he works on audio and video programming for Dark Reading and contributes to activities at Interop ITX, Black Hat, INsecurity, and ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
How Attackers Could Use Azure Apps to Sneak into Microsoft 365
Kelly Sheridan, Staff Editor, Dark Reading,  3/24/2020
Malicious USB Drive Hides Behind Gift Card Lure
Dark Reading Staff 3/27/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: This comment is waiting for review by our moderators.
Current Issue
6 Emerging Cyber Threats That Enterprises Face in 2020
This Tech Digest gives an in-depth look at six emerging cyber threats that enterprises could face in 2020. Download your copy today!
Flash Poll
State of Cybersecurity Incident Response
State of Cybersecurity Incident Response
Data breaches and regulations have forced organizations to pay closer attention to the security incident response function. However, security leaders may be overestimating their ability to detect and respond to security incidents. Read this report to find out more.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-10940
PUBLISHED: 2020-03-27
Local Privilege Escalation can occur in PHOENIX CONTACT PORTICO SERVER through 3.0.7 when installed to run as a service.
CVE-2020-10939
PUBLISHED: 2020-03-27
Insecure, default path permissions in PHOENIX CONTACT PC WORX SRT through 1.14 allow for local privilege escalation.
CVE-2020-6095
PUBLISHED: 2020-03-27
An exploitable denial of service vulnerability exists in the GstRTSPAuth functionality of GStreamer/gst-rtsp-server 1.14.5. A specially crafted RTSP setup request can cause a null pointer deference resulting in denial-of-service. An attacker can send a malicious packet to trigger this vulnerability.
CVE-2020-10817
PUBLISHED: 2020-03-27
The custom-searchable-data-entry-system (aka Custom Searchable Data Entry System) plugin through 1.7.1 for WordPress allows SQL Injection. NOTE: this product is discontinued.
CVE-2020-10952
PUBLISHED: 2020-03-27
GitLab EE/CE 8.11 through 12.9.1 allows blocked users to pull/push docker images.