CISCO addressed several critical IOS flaws that expose devices to remote attacks

Cisco has released security updates for its IOS Operating System to fix more than a dozen critical and high severity vulnerabilities.

Cisco has released updates for its IOS software to fix more than a dozen critical and high severity vulnerabilities that could be exploited by attackers to remotely take over company’s switches and routers.

Giving a close look at the flaws addressed by CISCO, we find the CVE-2017-12229 vulnerability that affects the REST API and that could be exploited by a remote attacker to bypass authentication and gain access to the web-based user interface of network devices running vulnerable versions of the IOS software.

“A vulnerability in the REST API of the web-based user interface (web UI) of Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass authentication to the REST API of the web UI of the affected software.” reads the CISCO security advisory.

“The vulnerability is due to insufficient input validation for the REST API of the affected software. An attacker could exploit this vulnerability by sending a malicious API request to an affected device. A successful exploit could allow the attacker to bypass authentication and gain access to the web UI of the affected software.”

IOS routers

CISCO also fixed the vulnerability CVE-2017-12230, it is a critical flaw that affects the web-based user interface that could be exploited by an authenticated attacker to escalate privileges. The problem is related to the creation of new users via the web interface that are given elevated privileges by default.

“A vulnerability in the web-based user interface (web UI) of Cisco IOS XE Software could allow an authenticated, remote attacker to elevate their privileges on an affected device.” reads the CISCO security advisory.

“The vulnerability is due to incorrect default permission settings for new users who are created by using the web UI of the affected software. An attacker could exploit this vulnerability by using the web UI of the affected software to create a new user and then logging into the web UI as the newly created user. A successful exploit could allow the attacker to elevate their privileges on the affected device.”

The last security critical flaw is CVE-2017-12240 and affects the DHCP relay subsystem in IOS and IOS XE software. The vulnerability could be exploited by a remote and unauthenticated attacker that can execute arbitrary code and gain full control of the targeted system. The flaw could be also exploited to cause a denial-of-service (DoS) condition by triggering a buffer overflow via specially crafted DHCPv4 packets.

“The vulnerability is due to a buffer overflow condition in the DHCP relay subsystem of the affected software. An attacker could exploit this vulnerability by sending a crafted DHCP Version 4 (DHCPv4) packet to an affected system. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a DoS condition.” states the CISCO advisory.

Cisco also addressed a total of 11 high severity vulnerability affecting various components of the IOS and/or IOS XE software.

The list of flaws includes DoS vulnerabilities affecting Catalyst switches, Integrated Services routers, industrial Ethernet switches, ASR 1000 series routers, and cBR-8 Converged Broadband routers.

The networking giant has also addressed two serious authentication bypass and certificate validation vulnerabilities.

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Pierluigi Paganini

(Security Affairs – CISCO IOS, hacking)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.