Connect with us

Hi, what are you looking for?


Network Security

Attackers Actively Targeting Cisco IOS XR Vulnerability

Cisco over the weekend published information on a vulnerability (CVE-2020-3566) in the IOS XR software that could be exploited to cause a denial of service condition. 

Cisco over the weekend published information on a vulnerability (CVE-2020-3566) in the IOS XR software that could be exploited to cause a denial of service condition. 

Cisco has warned that attackers are already attempting to exploit the vulnerability. 

The issue resides in the Distance Vector Multicast Routing Protocol (DVMRP) feature of IOS XR. Remote exploitation is possible without authentication, and could result in exhausted process memory and instability of other processes, including those of interior and exterior routing protocols. 

According to Cisco, the vulnerability exists due to insufficient queue management for Internet Group Management Protocol (IGMP) packets. As a result, an attacker could send crafted IGMP traffic to a vulnerable device to exploit the flaw. 

“This vulnerability affects any Cisco device that is running any release of Cisco IOS XR Software if an active interface is configured under multicast routing,” the company says. 

Cisco explains that administrators can use the show igmp interface command to determine whether multicast routing is enabled, and the show igmp traffic command to determine whether the device is receiving DVMRP traffic.

“This vulnerability results in memory exhaustion, which can impact other processes on the device. It is possible to recover the memory consumed by the IGMP process by restarting the IGMP process with the process restart igmp command,” the company notes. 

Advertisement. Scroll to continue reading.

There are no workarounds to address the issue, but Cisco has published information on various mitigations that customers can apply to remain protected. 

Mitigation steps for the vulnerabilities include implementing a rate limiter for the IGMP traffic, which increases the time needed for a successful exploitation, along with implementing an access control entry (ACE) to an existing interface access control list (ACL).

Tracked as CVE-2020-3566, the flaw has a CVSS score of 8.6. Cisco reveals that attackers are already attempting to exploit the vulnerability. 

Multiple iterations of ASR 9000 series aggregation services routers and IOS XR are affected. Cisco will release a software update to patch the bug but did not provide a timeframe for when that might happen. 

Related: Cisco Patches High-Severity Vulnerabilities in NX-OS Software

Related: Default Credentials Expose Cisco ENCS, CSP Appliances to Attacks

Related: Cisco Servers Hacked via Salt Vulnerabilities

Related: Cisco Patches Serious Vulnerabilities in Data Center Network Manager

Written By

Ionut Arghire is an international correspondent for SecurityWeek.

Click to comment

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

Join security experts as they discuss ZTNA’s untapped potential to both reduce cyber risk and empower the business.


Join Microsoft and Finite State for a webinar that will introduce a new strategy for securing the software supply chain.


Expert Insights

Related Content


Less than a week after announcing that it would suspended service indefinitely due to a conflict with an (at the time) unnamed security researcher...

Identity & Access

Zero trust is not a replacement for identity and access management (IAM), but is the extension of IAM principles from people to everyone and...

Data Breaches

OpenAI has confirmed a ChatGPT data breach on the same day a security firm reported seeing the use of a component affected by an...

Risk Management

The supply chain threat is directly linked to attack surface management, but the supply chain must be known and understood before it can be...

IoT Security

A group of seven security researchers have discovered numerous vulnerabilities in vehicles from 16 car makers, including bugs that allowed them to control car...


Patch Tuesday: Microsoft warns vulnerability (CVE-2023-23397) could lead to exploitation before an email is viewed in the Preview Pane.


A researcher at IOActive discovered that home security systems from SimpliSafe are plagued by a vulnerability that allows tech savvy burglars to remotely disable...


The latest Chrome update brings patches for eight vulnerabilities, including seven reported by external researchers.