A security researcher who goes by the name of Craig has discovered a critical flaw affecting Belkin network devices. that could be exploited by attackers to calculate the WPS PINs. In October 2014 Craig wrote on /dev/ttyS0 a post on a similar bug affecting D-Link routers.
This time the expert explained that Belkin implements a vulnerable procedure to generate its WPS PINs, an attacker just needs of the MAC and the serial number of a device to calculate the PIN.
Being a known obfuscation method, using the Firmware Analysis Tool binwalk he was able to de-obfuscate and extract the compressed firmware image, then he started the analysis of the code searching for the flaw. The researcher tested 24 Belkin routers, 80% of them were found using the flawed algorithm for the generation of the WPS PINs.
“MAC addresses are easily gathered by a wireless attacker; serial numbers can be a bit more difficult. Although serial numbers aren’t particularly random, GenerateDefaultPin uses the least significant 4 digits of the serial number, which are unpredictable enough to prevent an external attacker from reliably calculating the WPS pin.” reported the blog post.
Craig discovered that vulnerable devices use a PIN-generating algorithm based on information easy to retrieve, the MAC address and serial number. In order to retrieve the MAC address of a vulnerable device Craig exploited an ordinary 802.11 probe request to which Belkin devices reply the serial number.
“Since WiFi probe request/response packets are not encrypted, an attacker can gather the MAC address (the MAC address used by the algorithm is the LAN MAC) and serial number of a target by sending a single probe request packet to a victim access point. We just need to reverse the GenerateDefaultPin code to determine how it is using the MAC address and serial number to create a unique WPS pin (download PoC here):” continues the post.
The models of the allegedly vulnerable devices are listed below:
(Security Affairs – Belkin WPS Pin Algorithm, hacking)
Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.