CVE-2017-6074: Double Free
A flaw was found in the linux kernels implementation of DCCP protocol in which a local user could create influence timing in which a skbuff could be used after it had been freed by the kernel. An attacker is able to craft structures allocated in this free memory will be able to create memory corruption, privilege escalation or crash the system. An attacker must have a local account access on the system, this is not a remote attack. An attack requires IPV6 support to be enabled in the system.
Initial message:
https://groups.google.com/forum/#!topic/syzkaller/vGUxJLcdKY
Proposed patch:
https://patchwork.ozlabs.org/patch/728808/
Other sources
A use-after-free flaw was found in the way the Linux kernel's Datagram Congestion Control Protocol (DCCP) implementation freed SKB (socket buffer) resources for a DCCPPKTREQUEST packet when the IPV6RECVPKTINFO option is set on the socket. A local, unprivileged user could use this flaw to alter the kernel memory, allowing them to escalate their privileges on the system.
The dccprcvstateprocess function in net/dccp/input.c in the Linux kernel through 4.9.11 mishandles DCCPPKTREQUEST packet data structures in the LISTEN state, which allows local users to obtain root privileges or cause a denial of service (double free) via an application that makes an IPV6RECVPKTINFO setsockopt system call.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.18-419.el5 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.18-238.58.1.el5 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.18-348.33.1.el5 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.32-642.13.2.el6 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.32-220.70.1.el6 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.32-358.77.1.el6 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.32-431.78.1.el6 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.32-504.57.1.el6 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:2.6.32-573.40.1.el6 - Upgrade
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redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:3.10.0-514.6.1.rt56.430.el7 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-514.6.2.el7 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-229.49.1.ael7b - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-327.49.2.el7 - Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 1:3.10.0-514.rt56.219.el6 - Upgrade
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redhat/rhev-hypervisor7to a version that resolves this vulnerability.Fixed in 0:7.3-20170425.0.el6e - Upgrade
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redhat/rhev-hypervisor7to a version that resolves this vulnerability.Fixed in 0:7.3-20170425.0.el7e - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1 - Configuration
Add to /etc/modprobe.d/blacklist-dccp.conf: alias net-pf-10-proto-0-type-6 off
Linux kernel module (DCCP) autoloading via modprobe modprobe alias net-pf-10-proto-0-type-6 = off - Configuration
Add to /etc/modprobe.d/blacklist-dccp.conf: alias net-pf-10-proto-33-type-6 off
Linux kernel module (DCCP) autoloading via modprobe modprobe alias net-pf-10-proto-33-type-6 = off - Configuration
Add to /etc/modprobe.d/blacklist-dccp.conf: alias net-pf-2-proto-0-type-6 off
Linux kernel module (DCCP) autoloading via modprobe modprobe alias net-pf-2-proto-0-type-6 = off - Configuration
Add to /etc/modprobe.d/blacklist-dccp.conf: alias net-pf-2-proto-33-type-6 off
Linux kernel module (DCCP) autoloading via modprobe modprobe alias net-pf-2-proto-33-type-6 = off - Operational
Restart the system if the DCCP modules are already loaded (DCCP kernel modules will be unable to be unloaded while any network interfaces are active and the protocol is in use).
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2017-6074?
CVE-2017-6074 has been classified as a high severity vulnerability due to potential local privilege escalation.
How do I fix CVE-2017-6074?
To remediate CVE-2017-6074, upgrade your kernel to a version that is not affected, such as the patched versions provided by Red Hat or Debian.
What versions are affected by CVE-2017-6074?
CVE-2017-6074 affects various kernel versions, including older releases of Red Hat and Debian kernels prior to the security patches.
Who can be impacted by CVE-2017-6074?
Any local user on affected systems can exploit CVE-2017-6074 to perform actions that may lead to privilege escalation.
Is CVE-2017-6074 specific to certain distributions?
Yes, CVE-2017-6074 primarily affects certain versions of the Red Hat kernel and Linux distributions that utilize vulnerable kernel versions.