Effective 2019 Sep 15, Cisco will no longer publish non-Cisco product alerts. Cisco will continue to publish Security Advisories to address third-party software vulnerabilities per the Cisco Security Vulnerability Policy.
Multivendor Vulnerability Alert
Cisco IOS Software HTTP Service Loading Denial of Service Vulnerability
Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted device.
The vulnerability is due to improper handling of malformed HTTP responses when configuring a service from a remote host within Cisco IOS Software. An unauthenticated, remote attacker could exploit the vulnerability by convincing an administrative user to load a service from a remote host. If successful, the attacker could cause the device to fail, resulting in a DoS condition.
Cisco confirmed the vulnerability in a security advisory and released software updates.
Indicators of Compromise
Cisco has published a list of affected Cisco IOS Software releases in the Cisco bugID. The Vendor Announcements section of this alert contains a link to the bugID.
The vulnerability is due to improper handling of malformed HTTP responses when configuring a service from a remote host within Cisco IOS Software.
An unauthenticated, remote attacker could exploit this vulnerability by convincing an administrative user to install a service from a remote HTTP server. When the device running Cisco IOS Software processes HTTP responses from the remote host, the device may fail and become unresponsive, resulting in a DoS condition.
To exploit this vulnerability, an attacker must convince an administrative user on a device running Cisco IOS Software to load a service from a remote host under the control of the attacker. This operation is extremely risky and would likely not be performed in many environments, greatly reducing the chance of successful exploitation.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
These vulnerabilities were discovered and reported to Cisco Systems by Jaime Blasco of AlienVault.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to access critical systems.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
Cisco issued bug release notes for bug ID CSCts12249.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at email@example.com.
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.