Dropbear SSH Authorization-pending Connection Saturation DoS

medium Nessus Plugin ID 21023
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The remote SSH server is susceptible to denial of service attacks.


The remote host is running Dropbear, a small, open source SSH server.

The version of Dropbear installed on the remote host, by default, has a limit of 30 connections in the authorization-pending state; subsequent connections are closed immediately. This issue can be exploited trivially by an unauthenticated attacker to deny service to legitimate users.


Upgrade to Dropbear 0.48 or later.

See Also



Plugin Details

Severity: Medium

ID: 21023

File Name: dropbear_30_dos.nasl

Version: 1.18

Type: remote

Published: 3/8/2006

Updated: 11/15/2018

Dependencies: ssh_detect.nasl

Risk Information


Risk Factor: Medium

Score: 4.4


Risk Factor: Medium

Base Score: 5

Temporal Score: 3.9

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

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

Vulnerability Information

CPE: cpe:2.3:a:matt_johnston:dropbear_ssh_server:*:*:*:*:*:*:*:*

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 3/8/2006

Reference Information

CVE: CVE-2006-1206

BID: 17024