It's unclear just why US-CERT chose today to issue the alert on the well-known risks of leaving default passwords in place, but the Department of Homeland Security's National Cybersecurity and Communications Integration Center operation's warning was not in response to any new breaches or attacks.
US-CERT says any system with passwords accessible via the Internet are at risk. "Critical infrastructure and other important embedded systems, appliances, and devices are of particular concern," the alert says. "Attackers can easily identify and access internet-connected systems that use shared default passwords. It is imperative to change default manufacturer passwords and restrict network access to critical and important systems."
The vendor-default passwords are often publicly documented, and attackers can find systems using the defaults via Shodan searches or other scanning methods, US-CERT noted in its alert. The alert points to recent attacks that preyed on default passwords, such as the Carna botnet; the phony emergency alert on "zombies;" Stuxnet; and SSH access to jailbroken iPhones.
"Protecting critical infrastructure against growing and evolving cyber threats requires a layered approach that engages a wide range of partners. DHS, through the U.S.-Computer Emergency Readiness Team (US-CERT), actively collaborates and shares information with public and private sector partners every day to reduce adverse impacts on critical network systems," a DHS spokesperson said in a statement when asked about the new alert.
Moore in 2010 revealed that he had found hundreds of VoIP, DSL, ICS/SCADA, and Fibre Channel switch products vulnerable to a weakness he discovered in VxWorks -- a service that allowed backdoor access for diagnostic purposes that should have been deactivated by the vendors but was not. He ultimately found some 250,000 systems exposed by this so-called WDB agent, and then also discovered baked-in credentials in the VxWorks firmware that could allow an attacker to access the devices via FTP or telnet.
US-CERT recommends changing default passwords to strong ones prior to putting any network-connected system online, and employing alternative authentication methods, such as Kerberos, X.509 certificates, public keys, and multifactor authentication.
"Vendors can design systems to require password changes the first time a default password is used. Recent versions of DD-WRT wireless router firmware operate this way," the alert says. Routers, access points, switches, firewalls, databases, Web apps, ICS systems, embedded systems, remote terminal interfaces such as SSH and Telnet, and Web administrative interfaces often come with default passwords.
"Running a vulnerability scanner on your network can identify systems and services using default passwords. Freely available scanners include Metasploit and OpenVAS," US-CERT said in its alert.
Moore, who is chief security office at Rapid7, says Internet-wide scans may be controversial, but they are helping identify security issues.
"Basically, Internet-wide scans are helping us classify problems more accurately than before -- Shodan, my stuff, Dan Kaminsky's work, etc. -- are now being emulated by universities and private firms," Moore says. "There is some controversy about whether scanning like that is OK, let alone legalities under CFAA, etc., but it is the direction we are moving."
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