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.

Application Security //

Open Source

6/8/2018
08:05 AM
Larry Loeb
Larry Loeb
Larry Loeb
50%
50%

ZipSlip Flaw Lets Attackers Inject Malware Into Open Source Projects

The newly discovered ZipSlip flaw opens a big hole for malware in many open source projects. Here's what developers need to know.

Malware authors are so doggone creative. They find flaws in software that should be boring and stolid enough to avoid being exploited -- and then exploit them, anyway.

ZipSlip is an exploit like that.

It was first found by Snyk and disclosed on its website. The malware affects major archival formats such as ar, jar, war, cpio, apk, rar and 7z. Researchers report that it can be exploited on both client (user) machines and servers.

It's a way for an attacker to feed a poisoned archival file to a user, which allows them to write arbitrary files on the system that may end up with remote command execution.

Who would think unpacking a file could do that? Well, it can.

(Source: Snyk)
(Source: Snyk)

The vulnerability is exploited using a specially crafted archive that holds directory traversal filenames such as "../../evil.sh." With it, an attacker can unzip files outside the normal unzip path and then overwrite sensitive files such as critical OS libraries.

Programming languages, including JavaScript, Python, Ruby, .NET, Go, and Groovy, don't have an official archive for files and that makes developers do the unpacking on their own by using alternative libraries.

These libraries can be ZipSlip vulnerable, and Snyk published a list of affected open source libraries on GitHub. (See Microsoft's GitHub Deal: Following Developers & Security Into the Cloud.)

Snyk found that Java was the most affected programming language. The Oracle and Apache commons-compress APIs do offer some archiving support but do not publicly provide full extract capability. Java has no central library that offers high level processing of archive files. Snyk details that the lack of such a library led to vulnerable code snippets being hand-crafted and shared among developer communities like StackOverflow.

The effect on these libraries -- though many of them were fixed before Snyk disclosed -- can have a significant impact on many existing projects. Snyk found that Oracle, Amazon, Spring/Pivotal, Linkedin, Twitter, Alibaba, Jenkinsci, Eclipse, OWASP, SonarCube, OpenTable, Arduino, ElasticSearch, Selenium, Gradle and JetBrains all used the libraries or had vulnerable code within them that could be exploited.


Now entering its fifth year, the 2020 Vision Executive Summit is an exclusive meeting of global CSP executives focused on navigating the disruptive forces at work in telecom today. Join us in Lisbon on December 4-6 to meet with fellow experts as we define the future of next-gen communications and how to make it profitable.

The problem seems to not affect Ruby or Python. Snyk researchers noted:

We also vetted the Ruby and Python ecosystems and couldn't find any vulnerable code snippets or libraries. In fact, Python's zipfile was vulnerable until it was fixed in 2014. Ruby has a number of existing vulnerabilities that have been fixed in previous versions.

The way out of this may be to add validation code to a vulnerable snippet to test for directory traversal. If found, one must make sure to use the fixed libraries that Snyk has listed on GitHub. That process of finding out dependencies is a major pain, though.

The subtlety of the exploit and the lack of wide awareness of it make it a major security challenge for the enterprise. Though mediation will require some effort, the depth of the problem will make it rewarding.

Related posts:

— 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
Threaded  |  Newest First  |  Oldest First
Commentary
Cyberattacks Are Tailored to Employees ... Why Isn't Security Training?
Tim Sadler, CEO and co-founder of Tessian,  6/17/2021
Edge-DRsplash-10-edge-articles
7 Powerful Cybersecurity Skills the Energy Sector Needs Most
Pam Baker, Contributing Writer,  6/22/2021
News
Microsoft Disrupts Large-Scale BEC Campaign Across Web Services
Kelly Sheridan, Staff Editor, Dark Reading,  6/15/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
The State of Cybersecurity Incident Response
In this report learn how enterprises are building their incident response teams and processes, how they research potential compromises, how they respond to new breaches, and what tools and processes they use to remediate problems and improve their cyber defenses for the future.
Flash Poll
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2021-35210
PUBLISHED: 2021-06-23
Contao 4.5.x through 4.9.x before 4.9.16, and 4.10.x through 4.11.x before 4.11.5, allows XSS. It is possible to inject code into the tl_log table that will be executed in the browser when the system log is called in the back end.
CVE-2021-27649
PUBLISHED: 2021-06-23
Use after free vulnerability in file transfer protocol component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to execute arbitrary code via unspecified vectors.
CVE-2021-29084
PUBLISHED: 2021-06-23
Improper neutralization of special elements in output used by a downstream component ('Injection') vulnerability in Security Advisor report management component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to read arbitrary files via unspecified vectors.
CVE-2021-29085
PUBLISHED: 2021-06-23
Improper neutralization of special elements in output used by a downstream component ('Injection') vulnerability in file sharing management component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to read arbitrary files via unspecified vectors.
CVE-2021-29086
PUBLISHED: 2021-06-23
Exposure of sensitive information to an unauthorized actor vulnerability in webapi component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to obtain sensitive information via unspecified vectors.