Dropbear SSH Authorization-pending Connection Saturation DoS

Medium Nessus Plugin ID 21023


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: 2006/03/08

Updated: 2018/11/15

Dependencies: 10267

Risk Information

Risk Factor: Medium

CVSS v2.0

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:/a:matt_johnston:dropbear_ssh_server

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 2006/03/08

Reference Information

CVE: CVE-2006-1206

BID: 17024