Debian DLA-993-2 : linux regression update (Stack Clash)
Critical Nessus Plugin ID 100876
SynopsisThe remote Debian host is missing a security update.
DescriptionSeveral vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.
Li Qiang reported a reference counter leak in the ipxitf_ioctl function which may result into a use-after-free vulnerability, triggerable when a IPX interface is configured.
Tuomas Haanpaa and Matti Kamunen from Synopsys Ltd discovered that the NFSv2 and NFSv3 server implementations are vulnerable to an out-of-bounds memory access issue while processing arbitrarily long arguments sent by NFSv2/NFSv3 PRC clients, leading to a denial of service.
Ari Kauppi from Synopsys Ltd discovered that the NFSv2 and NFSv3 server implementations do not properly handle payload bounds checking of WRITE requests. A remote attacker with write access to a NFS mount can take advantage of this flaw to read chunks of arbitrary memory from both kernel-space and user-space.
It was discovered that the net_csk_clone_lock() function allows a remote attacker to cause a double free leading to a denial of service or potentially have other impact.
Johan Hovold found that the io_ti USB serial driver could leak sensitive information if a malicious USB device was connected.
Johan Hovold found a reference counter leak in the omninet USB serial driver, resulting in a use-after-free vulnerability. This can be triggered by a local user permitted to open tty devices.
Andrey Konovalov reported that the IPv6 fragmentation implementation could read beyond the end of a packet buffer. A local user or guest VM might be able to use this to leak sensitive information or to cause a denial of service (crash).
Andrey Konovalov reported that the SCTP/IPv6 implementation wrongly initialised address lists on connected sockets, resulting in a use-after-free vulnerability, a similar issue to CVE-2017-8890. This can be triggered by any local user.
CVE-2017-9076 / CVE-2017-9077 Cong Wang found that the TCP/IPv6 and DCCP/IPv6 implementations wrongly initialised address lists on connected sockets, a similar issue to CVE-2017-9075.
Andrey Konovalov reported a packet buffer overrun in the IPv6 implementation. A local user could use this for denial of service (memory corruption; crash) and possibly for privilege escalation.
The Qualys Research Labs discovered that the size of the stack guard page is not sufficiently large. The stack-pointer can jump over the guard-page and moving from the stack into another memory region without accessing the guard-page. In this case no page-fault exception is raised and the stack extends into the other memory region. An attacker can exploit this flaw for privilege escalation.
The default stack gap protection is set to 256 pages and can be configured via the stack_guard_gap kernel parameter on the kernel command line.
Further details can be found at https://www.qualys.com/2017/06/19/stack-clash/stack-clash.tx t
For Debian 7 'Wheezy', this problem has been fixed in version 3.2.89-2.
For Debian 8 'Jessie', this problem has been fixed in version 3.16.43-2+deb8u2.
For Debian 9 'Stretch', this problem has been fixed in version 4.9.30-2+deb9u2.
We recommend that you upgrade your linux packages.
NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpgrade the affected packages.