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CableTap/doc/advisories/bastille-19.wifi-dhcp-cm-mac-leak.txt
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| Bastille Tracking Number 19 | |
| CVE-2017-9477 | |
| Overview | |
| A vulnerability has been discovered that enables an attacker to discover the CM MAC of a Comcast customer's gateway by connecting to the "xfinitywifi" hotspot running on the gateway. | |
| Affected Platforms | |
| Cisco DPC3939, firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST | |
| Cisco DPC3939, firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST | |
| Proof-of-Concept | |
| When a user connects to an "xfinitywifi" hotspot on an affected gateway, the CM MAC, which is not normally known, is included in the DHCP ACK. | |
| Test Environment | |
| Cisco DPC3939, firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST | |
| Cisco DPC3939, firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST | |
| Mitigation | |
| Comcast customers can prevent this information leakage by disabling the "xfinitywifi" hotspot on their gateway. | |
| Recommended Remediation | |
| Configure the "xfinitywifi" DHCP server so that it does not leak the CM MAC. | |
| Credits | |
| Marc Newlin and Logan Lamb, Bastille | |
| Chris Grayson, Web Sight.IO |