Arista Networks EOS tcp_input Challenge ACKs Shared Counter Disclosure (SA0023)

Medium Nessus Plugin ID 107065

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VPR Score: 2.5


The version of Arista Networks EOS running on the remote device is affected by an information disclosure vulnerability.


The version of Arista Networks EOS running on the remote device is affected by a flaw in the Linux kernel implementation within file net/ipv4/tcp_input.c due to a failure to properly determine the rate of challenge ACK segments. An unauthenticated, remote attacker can exploit this issue to access the shared counter, thereby making it easier for the attacker to hijack TCP sessions via a blind in-window attack.


Contact the vendor for a fixed version. Alternatively, apply the hotfix or recommended mitigations referenced in the vendor advisory.

See Also

Plugin Details

Severity: Medium

ID: 107065

File Name: arista_eos_sa0023.nasl

Version: 1.6

Type: combined

Family: Misc.

Published: 2018/02/28

Updated: 2019/11/08

Dependencies: 107070

Risk Information

Risk Factor: Medium

VPR Score: 2.5

CVSS v2.0

Base Score: 5.8

Temporal Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:P

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

CVSS v3.0

Base Score: 4.8

Temporal Score: 4.2

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:arista:eos

Required KB Items: Host/Arista-EOS/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 2016/09/15

Vulnerability Publication Date: 2016/07/08

Reference Information

CVE: CVE-2016-5696

BID: 91704