Description of the problem: For a TCP-style socket, while processing the COOKIEECHO chunk in sctpsfdo51Dce(), after it has passed a series of sanity check, a new association would be created in sctpunpackcookie(), but afterwards, some processing maybe failed, and sctpassociationfree() will be called to free the previously allocated association, in sctpassociationfree(), skackbacklog value is decremented for this socket, since the initial value for skackbacklog is 0, after the decrement, it will be 65535, a wrap-around problem happens, and if we want to establish new associations afterward in the same socket, ABORT would be triggered since sctp deem the accept queue as full.
A remote attacker can block further connection to the particular sctp server socket by sending a specially crafted sctp packet.
Upstream patch: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d3217b15a19a4779c39b212358a5c71d725822ee
Acknowledgements:
Red Hat would like to thank Gopal Reddy Kodudula of Nokia Siemens Networks for reporting this issue.
arch/x86/kvm/vmx.c in the KVM subsystem in the Linux kernel before 3.17.2 on Intel processors does not ensure that the value in the CR4 control register remains the same after a VM entry, which allows host OS users to kill arbitrary processes or cause a denial of service (system disruption) by leveraging /dev/kvm access, as demonstrated by PRSETTSC prctl calls within a modified copy of QEMU.
It was reported [1] that iptables can allow protocols that do not have a protocol handler kernel module loaded.
Given following iptables ruleset: -P FORWARD DROP -A FORWARD -m sctp --dport 9 -j ACCEPT -A FORWARD -p tcp --dport 80 -j ACCEPT -A FORWARD -p tcp -m conntrack -m state ESTABLISHED,RELATED -j ACCEPT
One would assume that this allows SCTP on port 9 and TCP on port 80. Unfortunately, if the SCTP conntrack module is not loaded, this allows all SCTP communication to pass through, i.e. -p sctp -j ACCEPT
[1]: http://www.spinics.net/lists/netfilter-devel/msg33430.html
Last updated 24 July 2024
GNOME NetworkManager allows remote attackers to cause a denial of service (IPv6 traffic disruption) via a crafted MTU value in an IPv6 Router Advertisement (RA) message, a different vulnerability than CVE-2015-8215.