Arista Networks EOS/vEOS SegmentSmack TCP DoS (SA0036)

high Nessus Plugin ID 133724


The version of Arista Networks EOS running on the remote device is affected by a denial of service vulnerability.


The version of Arista Networks EOS or vEOS running on the remote device is affected by a denial of servics (DoS) vulnerability. A flaw named SegmentSmack was found in the way the Linux kernel handles specially crafted TCP packets. An unauthenticated, remote attacker can use this flaw to trigger time and calculation expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() functions by sending specially modified packets within ongoing TCP sessions which could lead to a CPU saturation and hence a denial of service on the system. Maintaining the denial of service condition requires continuous two-way TCP sessions to a reachable open port, thus the attacks cannot be performed using spoofed IP addresses.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Upgrade to Arista Networks EOS version EOS-, EOS-4.21.0F, EOS-4.20.8M, EOS-4.19.10M, EOS-4.18.9M, EOS-4.17.10M or later. Alternatively, apply the recommended mitigation referenced in the vendor advisory.

See Also

Plugin Details

Severity: High

ID: 133724

File Name: arista_eos_veos_sa0036.nasl

Version: 1.6

Type: combined

Family: Misc.

Published: 2/17/2020

Updated: 3/13/2020

Risk Information

CVSS Score Source: CVE-2018-5390


Risk Factor: Medium

Score: 4.4


Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

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


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:arista:eos

Required KB Items: Host/Arista-EOS/Version, Host/Arista-EOS/model

Exploit Ease: No known exploits are available

Patch Publication Date: 8/6/2018

Vulnerability Publication Date: 8/6/2018

Reference Information

CVE: CVE-2018-5390

BID: 104976

CERT: 962459