Security Experts:

Vulnerability in Realtek SDK Exposes Routers to Attacks

Routers from D-Link, TRENDnet and likely other vendors are vulnerable to remote code execution attacks due to a flaw in a component of the Realtek software development kit (SDK).

The issue was discovered by Ricky Lawshae, DVLabs security researcher and content developer at HP Enterprise Security. The expert reported his findings to HP’s Zero-Day Initiative (ZDI) in August 2014. Since Realtek hasn’t responded to any of ZDI’s attempts to report the vulnerability, the existence of the zero-day has been disclosed.

“The specific flaw exists within the miniigd SOAP service. The issue lies in the handling of the NewInternalClient requests due to a failure to sanitize user data before executing a system call,” ZDI wrote in its advisory.

The vulnerability (CVE-2014-8361) allows a remote, unauthenticated attacker to execute arbitrary code on affected systems with root privileges. ZDI has assigned the bug a CVSS score of 10.

The security hole affects the Realtek SDK used for RTL81xx chipsets. Lawshae says successfully reproduced the vulnerability on D-Link and TRENDnet routers, but devices from numerous other vendors use RTL81xx chipsets. It’s unclear how many small office and home (SOHO) routers are affected, but the researcher believes devices using the miniigb binary from the Realtek SDK are likely vulnerable.

“Given the stated purpose of Realtek SDK, and the nature of the vulnerability, the only salient mitigation strategy is to restrict interaction with the service to trusted machines,” ZDI said. “Only the clients and servers that have a legitimate procedural relationship with products using Realtek SDK service should be permitted to communicate with it. This could be accomplished in a number of ways, most notably with firewall rules/whitelisting.”

Realtek has not responded to SecurityWeek’s request for comment by the time of publication.

Vulnerabilities in D-Link and Trendnet wireless routers are not uncommon. Earlier this year, researchers reported uncovering several flaws related to the ncc/ncc2 service used by devices from these vendors. Both D-Link and Trendnet released firmware updates to address the issues.

However, not all firmware updates are as efficient in addressing security bugs as they should be. A researcher reported last month that D-Link had failed to properly patch some vulnerabilities related to the Home Network Administration Protocol (HNAP).

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.