Phone : +91 95 8290 7788 | Email : sales@itmonteur.net

Register & Request Quote | Submit Support Ticket

Home » Cyber Security News » SACK Panic and three other vulnerabilities discovered in Linux and FreeBSD kernels

SACK Panic and three other vulnerabilities discovered in Linux and FreeBSD kernels

 

  • All these vulnerabilities are related to the minimum segment size (MSS) and TCP selective acknowledgment (SACK) capabilities.
  • ‘SACK Panic’ is the most severe vulnerability of all the flaws.

Four TCP networking vulnerabilities in FreeBSD and Linux kernels have been discovered by security researchers recently. All these vulnerabilities are related to the minimum segment size (MSS) and TCP selective acknowledgment (SACK) capabilities.

SACK PANIC, the serious one

In a report, Netflix Information Security’s Jonathan Looney has revealed that ‘SACK Panic’ is the most severe vulnerability of all the flaws. Tracked as CVE-2019-11477, the vulnerability has been marked with a CVSS score of 7.5. It could permit an attacker to remotely induce a kernel panic within recent Linux operating systems.

A kernel panic is a kind of vulnerability where an operating system cannot be recovered easily. This could force a restart of a targeted host, causing a temporary shutdown in services.

The SACK Panic flaw impacts Linux kernel version 2.6.29 and later. It can be addressed by deploying PATCH_net_1_4.patch. Additionally, the versions of the Linux kernel up to 4.14 require a second patch PATCH_net_1a.patch.

The other way to mitigate the issue is by completely disabling SACK processing on the system.

What are the other flaws?

As per Red Hat, the two other issues that impact the kernel’s TCP processing subsystem are CVE-2019-11478 (dubbed SACK Slowness) and CVE-2019-11479. These flaws are considered to be moderate severity vulnerabilities.

The CVE-2019-11478 can be exploited by sending a crafted sequence of SACKs which will fragment the TCP retransmission queue, while CVE-2019-11479 allows attackers to trigger a DoS attack.

CVE-2019-5599 is the FreeBSD counterpart of CVE-2019-11478. The flaw impacts FreeBSD 12 installations using the RACK TCP Stack. It can be abused by delivering “a crafted sequence of SACKs which will fragment the RACK send map.”

Linux and FreeBSD admins and users can address CVE-2019-11478 by applying PATCH_net_2_4.patch. The second issue, CVE-2019-11479, can be addressed by using PATCH_net_3_4.patch and PATCH_net_4_4.patch security patches. CVE-2019-5599 can be patched only by applying ‘ ‘split_limit.patch’ and set the net.inet.tcp.rack.split_limit sysctl’’ to a reasonable value to limit the size of the SACK table.

Information Security - InfoSec - Cyber Security - Firewall Support Providers Company in India

 

What is Firewall? A Firewall is a network security device that monitors and filters incoming and outgoing network traffic based on an organization's previously established security policies. At its most basic, a firewall is essentially the barrier that sits between a private internal network and the public Internet.

 

Secure your network at the gateway against threats such as intrusions, Viruses, Spyware, Worms, Trojans, Adware, Keyloggers, Malicious Mobile Code (MMC), and other dangerous applications for total protection in a convenient, affordable subscription-based service. Modern threats like web-based malware attacks, targeted attacks, application-layer attacks, and more have had a significantly negative effect on the threat landscape. In fact, more than 80% of all new malware and intrusion attempts are exploiting weaknesses in applications, as opposed to weaknesses in networking components and services. Stateful firewalls with simple packet filtering capabilities were efficient blocking unwanted applications as most applications met the port-protocol expectations. Administrators could promptly prevent an unsafe application from being accessed by users by blocking the associated ports and protocols.

 

Firewall Firm is an IT Monteur Firewall Company provides Managed Firewall Support, Firewall providers , Firewall Security Service Provider, Network Security Services, Firewall Solutions India , New Delhi - India's capital territory , Mumbai - Bombay , Kolkata - Calcutta , Chennai - Madras , Bangaluru - Bangalore , Bhubaneswar, Ahmedabad, Hyderabad, Pune, Surat, Jaipur, Firewall Service Providers in India, Welcome to IT Monteur's Firewall Firm, India's No1 Managed Enterprise Network Security Firewall Support Provider Company in India, Firewall Firm Provider Complete range of Juniper Firewall Support , Cisco Firewall Support , Check Point Firewall Support , Palo Alto Firewall Support , FortiGate Firewall Support , Forcepoint Firewall Support , Sophos Firewall Support , WatchGuard Firewall Support , Baracuda Firewall Support , SonicWall Firewall Support , Gajshield Firewall Support , Seqrite Firewall Support , Firewall , Hardware Firewall , Software Firewall , Firewall India , Firewall , Network Firewall , Firewall Support , Firewall Monitoring , Firewall VPN , WAF Website Firewall , Firewall Security , Firewall India , Firewalls Support Provider in India , Firewall Support Services Provider Company in India

Sales Number : +91 95 8290 7788 | Support Number : +91 94 8585 7788
Sales Email : sales@itmonteur.net | Support Email : support@itmonteur.net

Register & Request Quote | Submit Support Ticket