F5 Networks BIG-IP : Linux kernel TCP ISN vulnerability (K15301)

critical Nessus Plugin ID 78170


The remote device is missing a vendor-supplied security patch.


The (1) IPv4 and (2) IPv6 implementations in the Linux kernel before 3.1 use a modified MD4 algorithm to generate sequence numbers and Fragment Identification values, which makes it easier for remote attackers to cause a denial of service (disrupted networking) or hijack network sessions by predicting these values and sending crafted packets. (CVE-2011-3188)


Attackers may be able to cause denial-of-service (DoS) or hijack network sessions by predicting sequence number values and sending crafted packets.

This issue affects control-plane traffic generated by the Linux kernel, and does not affect data-plane traffic.Outbound connections initiated from the BIG-IP system by administrative applications such as BIG-IP health monitors, SNMP, SMTP, SSH, network time protocol (NTP), and so on, are processed by the Linux operating system, and may be exploited by this vulnerability. For more information, refer to K13284: Overview of management interface routing (11.x and later).

Note : Vulnerability scanners searching for this vulnerability will sometimes return false positives, as they depend on a low entropy value in certain sequence numbers for this vulnerability. Identifying a low entropy value in these tests may be inherently prone to false positives. For more information on vulnerability scanners, refer toK31046057: CVE security vulnerability scanners may report false positive results.


Upgrade to one of the non-vulnerable versions listed in the F5 Solution K15301.

See Also




Plugin Details

Severity: Critical

ID: 78170

File Name: f5_bigip_SOL15301.nasl

Version: 1.9

Type: local

Published: 10/10/2014

Updated: 3/10/2021

Configuration: Enable paranoid mode

Risk Information


Risk Factor: Medium

Score: 5.2


Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.6

Vector: AV:N/AC:L/Au:N/C:N/I:P/A:P

Temporal Vector: E:ND/RL:OF/RC:C


Risk Factor: Critical

Base Score: 9.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Vulnerability Information

CPE: cpe:/a:f5:big-ip_access_policy_manager, cpe:/a:f5:big-ip_application_security_manager, cpe:/a:f5:big-ip_application_visibility_and_reporting, cpe:/a:f5:big-ip_global_traffic_manager, cpe:/a:f5:big-ip_link_controller, cpe:/a:f5:big-ip_local_traffic_manager, cpe:/a:f5:big-ip_wan_optimization_manager, cpe:/a:f5:big-ip_webaccelerator, cpe:/h:f5:big-ip, cpe:/h:f5:big-ip_protocol_security_manager

Required KB Items: Host/local_checks_enabled, Host/BIG-IP/hotfix, Host/BIG-IP/modules, Host/BIG-IP/version, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 7/25/2014

Vulnerability Publication Date: 5/24/2012

Reference Information

CVE: CVE-2011-3188

BID: 49289