Cisco informed customers on Wednesday that several of its products are exposed to denial-of-service (DoS) attacks due to a vulnerability in the Snort detection engine.
The flaw, tracked as CVE-2021-1285 and rated high severity, can be exploited by an unauthenticated, adjacent attacker — the attacker is on the same layer 2 domain as the victim — to cause a device to enter a DoS condition by sending it specially crafted Ethernet frames.
Cisco says the vulnerability is in the Ethernet Frame Decoder component of Snort. The issue impacts all versions of the popular open source intrusion prevention and intrusion detection system (IPS/IDS) prior to 2.9.17, which contains a patch.
CVE-2021-1285 has been found to impact Integrated Service Router (ISR), Catalyst Edge software and platform, and 1000v series Cloud Services Router products. These devices are affected if they are running a vulnerable version of Cisco UTD Snort IPS engine software for IOS XE or Cisco UTD Engine for IOS XE SD-WAN, and they are configured to pass Ethernet frames to Snort.
Cisco says the vulnerability is related to a Firepower Threat Defense (FTD) issue patched in October 2020.
The vulnerability was found during the resolution of a support case and there is no evidence that it has been exploited in malicious attacks.
Cisco on Wednesday also published advisories for a dozen other vulnerabilities, which have been assigned a medium severity rating. These impact Webex, SD-WAN, ASR, Network Services Orchestrator, IP phones, and Email Security Appliance products, and they can lead to information disclosure, path traversal, authorization bypass, DoS attacks, privilege escalation, and SQL injection.