Actively exploited in the wild
Cisco IOS Denial-of-Service Vulnerability
Cisco - IOS · Listed in the CISA KEV since 2023-05-19. This indicates confirmed attacks in production environments.
Required action: Apply updates per vendor instructions.
CVE-2004-1464
MediumCVSS 5.9KEVSummary
Cisco IOS 12.2(15) and earlier allows remote attackers to cause a denial of service (refused VTY (virtual terminal) connections), via a crafted TCP connection to the Telnet or reverse Telnet port.
Risk Assessment
An attacker can prevent administrators from remotely logging into the device, blocking management and incident response, which may lead to prolonged outages.
Recommendation
Upgrade Cisco IOS to a fixed version and restrict access to Telnet/reverse Telnet ports using access control lists and authentication.
Other vulnerabilities in Cisco IOS
See all- CVE-2016-1478High
Cisco IOS versions 15.5(3)S3, 15.6(1)S2, 15.6(2)S1, and 15.6(2)T1 improperly dequeue invalid NTP packets, allowing remote attackers to cause a denial of service (interface wedge) by sending many crafted NTP packets.
- CVE-2015-0649High
Cisco IOS versions 12.2, 12.4, 15.0, 15.2, and 15.3 allow remote attackers to cause a denial of service (device reload) via malformed Common Industrial Protocol (CIP) TCP packets.
- CVE-2015-0647High
Cisco IOS versions 12.2, 12.4, 15.0, 15.2, and 15.3 allow remote attackers to cause a denial of service (device reload) via malformed Common Industrial Protocol (CIP) UDP packets.
- CVE-2015-0638High
In Cisco IOS versions 12.2, 12.4, 15.0, 15.2, and 15.3, configuring a VRF interface allows remote attackers to cause a denial of service (interface queue wedge) via crafted ICMPv4 packets.
- CVE-2008-4128MediumActively exploited
Multiple CSRF vulnerabilities in the HTTP Administration component of Cisco IOS 12.4 on the 871 Integrated Services Router allow remote attackers to execute arbitrary commands. The attack involves requests to the /level/15/exec/- URI with the "show privilege" command and to the /level/15/exec/-/configure/http URI with the "alias exec" command.
- CVE-1999-0063Medium
Cisco IOS 12.0 and other versions can be crashed by malicious UDP packets to the syslog port.
- CVE-1999-0445Medium
In some versions of IOS 12.0 on Cisco routers running NAT, some packets may not be filtered by input access list filters.
- CVE-1999-0162Medium
The 'established' keyword in some Cisco IOS software allowed an attacker to bypass filtering.
- CVE-1999-0159Low
Attackers can crash a Cisco IOS router or device, provided they can get to an interactive prompt (such as a login). This applies to some IOS 9.x, 10.x, and 11.x releases.
- CVE-1999-0160High
Some classic Cisco IOS devices have a vulnerability in PPP CHAP authentication, allowing unauthorized PPP connections to be established.
Original NVD description (English source)
Cisco IOS 12.2(15) and earlier allows remote attackers to cause a denial of service (refused VTY (virtual terminal) connections), via a crafted TCP connection to the Telnet or reverse Telnet port.