Linux PCs, Servers, Gadgets Can Be Crashed by ‘Ping of Death’ Network Packets writes that it is possible to crash and slow-down network-facing Linux servers, PCs, smartphones and tablets, and gadgets, by sending them a series of maliciously crafted packets.
Netflix has published a security paper with many details. There are four vulnerabilities, three of them for Linux and one for FreeBSD. The vulnerabilities specifically relate to the Maximum Segment Size (MSS) and TCP Selective Acknowledgement (SACK) capabilities.
The Register reports that patches and mitigations are available (can be applied by hand or you can wait for a security fix).
In the mean time a key workaround for Linux devices you administer is to set /proc/sys/net/ipv4/tcp_sack to 0, which disables the most vulnerable features on Linux.
According to Cisco advisory the proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is already publicly available. I have not seen that code yet but I would be intetested to test it against some devices.
Another networking vulnerability that has been on on security news headlines lately has has been related to quite recent incresingly popular network time protocol. It’s Surprisingly Easy to Hack the Precision Time Protocol article writes that when it comes to synchronizing large and important networks, every microsecond counts, and NTP is not always accurate enough. One of the most effective approach for this is called IEEE 1588-2008 or the Precision Time Protocol (PTP). A team of researchers from IBM and Marist College recently identified a remarkably simple but effective way to hack a PTP network: The researchers were able to infiltrate the network by “sniffing” out the ANNOUNCE and SYNC packets of the legitimate master clock. Next, they created a rogue master clock.