SNMP issues in many devices allow disclosure of data

Pierluigi Paganini May 19, 2014

Researchers at Rapid7 disclosed a series of vulnerabilities in many devices that allow data disclosure from the SNMP community string.

Researchers at Rapid7 have discovered problems in SNMP on embedded devices which can can cause the exposure of critical information. As explained in the official blog post during the analysis the experts discovered devices which expose information that would be classified as benign or public, but these issues can be exploited to gain access to further sensitive information. Some of the device in question are end-of-life, but it is possible to find them on secondary markets such as Ebay.

In three cases, the appliances allowed the extraction of authentication data via the read only community string of public, surprising that in two cases this was the default behavior. The public SNMP community string enables outside access to device information, the impact of these flaws is not negligible, a large number of devices are currently exposing SNMP to the public Internet, an attacker can easily find them using Shodan search engine.

The first involves a Brocade load balancer (you might have one of these in your rack). The second and third involve some consumer-grade modems from Ambit (now Ubee) and Netopia (now Motorola). For the modem/routers, you might have one of these at a remote office, warehouse, guest WIfi network, water treatment plant, etc. They are quite common in office and industrial environments where IT doesn’t have a strong presence. Shodan identifies 229,409 Ambit devices exposed to the internet, and 224,544 of the Netopia devices. Of theres, 187,000 appear to be in the United States.” reports Rapid7.

The most serious problem was identified in Brocade ServerIron ADX 1016-2-PREM, TrafficWork Version 12.5.00T403 application load balancer that stores user credentials in the SNMP MIB tables.

SNMP flaws

SNMP is enabled by default an attacker can steal password hashes that could be easily cracked.

“It is used by a number of companies out there to front end various applications on the corporate network,” Heiland said, adding that a Shodan search for the device turned up 9,000 facing the Internet. “It’s a lot lower number than the home routers and modems, but that’s 9,000 corporations that could potentially, if the passwords were weak enough, be opened up to remote attacks.”  added Deral Heiland, senior security consultant.

The researchers also discovered similar issues in the other cable modems, including Ambit U10C019, Ubee DDW3611 cable modems and the Netopia (manufactured by Motorola) 3347 series of DSL modems.

SNMP flaws 2

The problems detected for cable modems are not limited to the disclosure of users’ credential, but also WEP keys, WPA PSK and SSID information, meanwhile for the DSL modems WEP keys, WPA PSK and SSID are lacking.

In the cases of Ambit and Ubee cable modems SNMP is not enabled by default, cable providers are likely enabling it on the uplink side of the modems to allow remote.

Rapid7 has already issued the Metasploit modules to exploit the above vulnerabilities, as explained in the blog post.

“This type of data is unexpected to be stored in MIB tables for SNMP. It’s atypical,”  “The problem is that the vulnerabilities are also in existing hardware and in current devices. I believe that 100 percent.” added Heiland.

It’s important to note that manufactures are not setting these devices up with SNMP enabled and Internet-facing configurations, according researchers, service providers are responsible for turning the service on, likely for remote management.

“But still, I don’t know why it’s important to have pre-shared keys and passwords available over this,” “That’s where the flaw is. It’s an implementation and deployment issue. When you set up SNMP, you don’t want to leave public community strings in place.” Heiland said. 

Researchers revealed to have already discovered similar flaws in other devices that should be made public soon after the ethical disclosure to the manufacturers.

Pierluigi Paganini

(Security Affairs –  SNMP,hacking)  

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