CVE-2023-20198: Zero-Day Vulnerability in Cisco IOS XE Exploited in the Wild
2023-10-17 01:14:47 Author: www.tenable.com(查看原文) 阅读量:48 收藏

CVE-2023-20198: Zero-Day Vulnerability in Cisco IOS XE Exploited in the Wild

A maximum severity CVSS 10 zero-day vulnerability in Cisco IOS XE has been exploited in the wild. Organizations should apply the mitigation steps from Cisco as soon as possible until patches are released.

Background

On October 16, Cisco’s Talos published a blog post warning of a zero-day vulnerability in the Web User Interface (Web UI) feature of Cisco IOS XE software that has been exploited in the wild by unknown threat actors. Cisco warns that successful exploitation could allow attackers to create an account with level 15 access, the highest privilege level that gives the user full control over the router.

Cisco Talos was alerted to the issue after a support case was investigated on September 28th. During their investigation, Cisco found evidence as early as September 18th, where a new user account was created by an unknown and suspicious IP address. Additional threat activity was observed on October 12, where a user account was created and a configuration file was uploaded to allow the threat actor to execute commands and maintain persistent access to the affected device.

Analysis

CVE-2023-20198 is a privilege escalation vulnerability affecting Cisco IOS XE software, receiving the highest possible CVSS score of 10. Successful exploitation of this vulnerability would allow an attacker to create a user account with full administrative privileges. While no details have been provided, Cisco states that the vulnerability lies within the Web UI feature.

CVE-2021-1435 abused to install an implant

According to Cisco Talos, the threat actors were observed using an older vulnerability, CVE-2021-1435 to install an implant after abusing CVE-2023-20198 to gain access to the device. CVE-2021-1435 is a command injection vulnerability affecting the Web UI of Cisco IOS XE software. The vulnerability would allow an authenticated attacker to inject arbitrary code that would be executed as the root user. This vulnerability was patched by Cisco in March 2021. Curiously, Cisco Talos blog mentions that they have observed devices that were fully patched against CVE-2021-1435, in which the threat actors were still able to deploy their implant. At the time their blog was released, it was not known how they were able to do so.

A great analysis of the observed implant can be found in the blog post released by Cisco Talos. We strongly recommend referring to the blog post for more information on the observations made during their investigation of compromised devices.

Historic exploitation of Cisco IOS XE

CVE-2023-20198 is the second zero-day in Cisco IOS XE disclosed this month. On September 28, Cisco released an advisory warning of CVE-2023-20109, a medium severity out-of-bounds write vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) feature of Cisco IOS and Cisco IOS XE. The vulnerability could allow a remote, authenticated attacker with administrator privileges on a key server or group member to execute code on or crash a vulnerable device. Cisco’s advisory states that they observed attempted exploitation of the GET VPN feature and identified the vulnerability after performing a review of the code as part of their investigation.

Proof of concept

At the time this blog was published on October 16, no proof-of-concept code was found to be publicly available for CVE-2023-20198.

Solution

As of October 16, Cisco’s security advisory states that “Cisco will provide updates on the status of this investigation and when a software patch is available.” In the absence of patches, Cisco does recommend disabling the HTTP Server feature on any Cisco IOS XE systems that are internet-facing. The advisory provides steps on how to disable the feature as well as steps on how to determine if the HTTP Server feature is enabled. Additionally, the Cisco security advisory outlines an additional command to run after disabling the HTTP Server feature, to ensure that the feature is not re-enabled after a system reload.

The blog from Cisco Talos as well as the Cisco security advisory also include some indicators of compromise to assist in incident response investigations.

Identifying affected systems

A list of Tenable plugins to identify affected systems can be located on the individual CVE page for CVE-2023-20198. This link will display all available plugins for this vulnerability, including upcoming plugins in our Plugins Pipeline.

While patches have not yet been released, you can identify Cisco IOS XE systems across your organization by utilizing the asset detection Plugin ID 67217.

Get more information

Join Tenable's Security Response Team on the Tenable Community.

Learn more about Tenable One, the Exposure Management Platform for the modern attack surface.

Scott Caveza

Scott Caveza

Scott joined Tenable in 2012 as a Research Engineer on the Nessus Plugins team. Over the years, he has written hundreds of plugins for Nessus, and reviewed code for even more from his time being a team lead and manager of the Plugins team. Previously leading the Security Response team and the Zero Day Research team, Scott is currently a member of the Security Response team, helping the research organization respond to the latest threats. He has over a decade of experience in the industry with previous work in the Security Operations Center (SOC) for a major domain registrar and web hosting provider. Scott is a current CISSP and actively maintains his GIAC GWAPT Web Application Penetration Tester certification.

Interests outside of work: Scott enjoys spending time with his family, camping, fishing and being outdoors. He also enjoys finding ways to break web applications and home renovation projects.

Related Articles

  • Exposure Management

Cybersecurity News You Can Use

Enter your email and never miss timely alerts and security guidance from the experts at Tenable.

Tenable Vulnerability Management

Formerly Tenable.io

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy.

Your Tenable Vulnerability Management trial also includes Tenable Lumin and Tenable Web App Scanning.

Tenable Vulnerability Management

Formerly Tenable.io

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Purchase your annual subscription today.

65 assets

Choose Your Subscription Option:

Thank You

Thank you for your interest in Tenable.io. A representative will be in touch soon.

Try Tenable Nessus Professional Free

FREE FOR 7 DAYS

Tenable Nessus is the most comprehensive vulnerability scanner on the market today.

NEW - Tenable Nessus Expert
Now Available

Nessus Expert adds even more features, including external attack surface scanning, and the ability to add domains and scan cloud infrastructure. Click here to Try Nessus Expert.

Fill out the form below to continue with a Nessus Pro Trial.

Buy Tenable Nessus Professional

Tenable Nessus is the most comprehensive vulnerability scanner on the market today. Tenable Nessus Professional will help automate the vulnerability scanning process, save time in your compliance cycles and allow you to engage your IT team.

Buy a multi-year license and save. Add Advanced Support for access to phone, community and chat support 24 hours a day, 365 days a year.

Tenable.io

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy.

Your Tenable Vulnerability Management trial also includes Tenable Lumin and Tenable Web App Scanning.

Tenable.io

BUY

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Purchase your annual subscription today.

65 assets

Choose Your Subscription Option:

Thank You

Thank you for your interest in Tenable.io. A representative will be in touch soon.

Try Tenable Web App Scanning

Formerly Tenable.io Web Application Scanning

Enjoy full access to our latest web application scanning offering designed for modern applications as part of the Tenable One Exposure Management platform. Safely scan your entire online portfolio for vulnerabilities with a high degree of accuracy without heavy manual effort or disruption to critical web applications. Sign up now.

Your Tenable Web App Scanning trial also includes Tenable Vulnerability Management and Tenable Lumin.

Buy Tenable Web App Scanning

Formerly Tenable.io Web Application Scanning

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Purchase your annual subscription today.

Try Tenable Lumin

Visualize and explore your exposure management, track risk reduction over time and benchmark against your peers with Tenable Lumin.

Your Tenable Lumin trial also includes Tenable Vulnerability Management and Tenable Web App Scanning.

Buy Tenable Lumin

Contact a Sales Representative to see how Tenable Lumin can help you gain insight across your entire organization and manage cyber risk.

Thank You

Thank you for your interest in Tenable Lumin. A representative will be in touch soon.

Request a demo of Tenable Security Center

Formerly Tenable.sc

Please fill out this form with your contact information.

A sales representative will contact you shortly to schedule a demo.

* Field is required

Request a demo of Tenable OT Security

Formerly Tenable.ot

Get the Operational Technology Security You Need.

Reduce the Risk You Don’t.

Request a demo of Tenable Identity Exposure

Formerly Tenable.ad

Continuously detect and respond to Active Directory attacks. No agents. No privileges.

On-prem and in the cloud.

Request a Demo of Tenable Cloud Security

Exceptional unified cloud security awaits you!

We’ll show you exactly how Tenable Cloud Security helps you deliver multi-cloud asset discovery, prioritized risk assessments and automated compliance/audit reports.

Thank You

Thank you for your interest in Tenable Cloud Security. A representative will be in touch soon.

See
Tenable One
In Action

Exposure management for the modern attack surface.

See Tenable Attack Surface Management In Action

Formerly Tenable.asm

Know the exposure of every asset on any platform.

Thank You

Thank you for your interest in Tenable Attack Surface Management. A representative will be in touch soon.

Try Tenable Nessus Expert Free

FREE FOR 7 DAYS

Built for the modern attack surface, Nessus Expert enables you to see more and protect your organization from vulnerabilities from IT to the cloud.

Already have Tenable Nessus Professional?
Upgrade to Nessus Expert free for 7 days.

Buy Tenable Nessus Expert

Built for the modern attack surface, Nessus Expert enables you to see more and protect your organization from vulnerabilities from IT to the cloud.

Try Nessus Expert Free

FREE FOR 7 DAYS

Built for the modern attack surface, Nessus Expert enables you to see more and protect your organization from vulnerabilities from IT to the cloud.

Already have Nessus Professional?
Upgrade to Nessus Expert free for 7 days.

Buy Tenable Nessus Expert

Built for the modern attack surface, Nessus Expert enables you to see more and protect your organization from vulnerabilities from IT to the cloud.


文章来源: https://www.tenable.com/blog/cve-2023-20198-zero-day-vulnerability-in-cisco-ios-xe-exploited-in-the-wild
如有侵权请联系:admin#unsafe.sh