Cisco IOS, IOS XR, and IOS XE: information disclosure flaw under attack

What is affected

Cisco IOS, IOS XR, and IOS XE is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

Cisco IOS, IOS XR, and IOS XE contain insufficient condition checks in the part of the code that handles Internet Key Exchange version 1 (IKEv1) security negotiation requests. contains an information disclosure vulnerability in the Internet Key Exchange version 1 (IKEv1) that could allow an attacker to retrieve memory contents. Successful exploitation could allow the attacker to retrieve memory contents, which can lead to information disclosure.

What an attacker can do

This is a information disclosure flaw. It lets an attacker read data they are not supposed to see, such as memory contents, credentials or internal files. It is often the first step of a larger attack.

How it is reached

Over the internet or network

Access the attacker needs

No account needed

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. Update Cisco IOS, IOS XR, and IOS XE now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply updates per vendor instructions.

Vendor advisories and fixes

• sec.cloudapps.cisco.comsec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160916-ik

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on May 19, 2023, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by June 9, 2023, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 88% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99.8% of all scored vulnerabilities.

Its CVSS severity score is 7.5 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

The server IKEv1 implementation in Cisco IOS 12.2 through 12.4 and 15.0 through 15.6, IOS XE through 3.18S, IOS XR 4.3.x and 5.0.x through 5.2.x, and PIX before 7.0 allows remote attackers to obtain sensitive information from device memory via a Security Association (SA) negotiation request, aka Bug IDs CSCvb29204 and CSCvb36055 or BENIGNCERTAIN.