Earlier this week, Czech security experts led by Jan Vykopal, head of the security project of Masaryk University released a report describing “Chuck Norris”, a BoTnet they discovered running on compromised broadband routers that attempts to intercept sensitive information such as user passwords, bank account details and private email account information.
Once installed, the bot blocks remote communication ports and begins to scan the network for other vulnerable machines. Controlled via IRC, the worm itself can be terminated by restarting the router as it is installed in RAM. However, variations may exist that install itself into NVRAM that may not be so easily removed.
While the Czech experts identified the BoTnet’s footprint only to have extend across Europe, China & South America, North America may not be far behind. Earlier last year, DroneBL – an organization that monitors abuse of infected machines identified a potential PoC (proof of concept) BoTnet called Psyb0t that was soon shut down.
According to this white paper on Psybot, ADSL modem/routers based on the Texas Instruments TNETD7300, similar to the NB5 modem/router manufactured by NetComm were exploitable using their web interfaces that were exposed on the WAN side.
DroneBL team summarized the Psybot characteristics as:
- was the first botnet worm to target routers and DSL modems
- contained shellcode for many mipsel devices
- was not targeting PCs or servers
- used multiple strategies for exploitation, including bruteforce username and password combinations
- harvested usernames and passwords through deep packet inspection
- could scan for exploitable phpMyAdmin and MySQL servers
The DroneBL blog on this botnet estimated about 100,000 Mipsel – a port of Debian Linux for MIPS processors – devices as infected. While the BoTnet is no longer supposed to be active, the short time it took to spread to 100,000 devices is certainly cause for alarm.
The average gateway device used by small-businesses and/or individual users does not enjoy the typical protection the user’s computers may have on the internal network such as virus and malware scanners or periodic software updates. This makes it all the more appealing to potential attackers. In addition, as any external traffic gets routed through the device, it’s the ideal location to intercept sensitive information to/from all network resources.
Guidelines to protect your Gateways & Routers
To reduce potential risk of compromise to your network, ensure the gateway devices at least have;
- No administrative interfaces (Web, Shell) exposed to the WAN side
- Strong password policies
- Use alphanumerically complex passwords
- Change passwords regularly
- Do not reuse passwords
- Changed default user/admin names (Such as ‘admin’)
- Latest firmware/patches applied
- Logging enabled and monitored routinely.




Recent Comments