Rockwell Automation MicroLogix 1100 PLC < FRN 10.0 Authentication Mechanism DoS

critical Nessus Plugin ID 84570


The remote web server running on the MicroLogix 1100 PLC is affected by a denial of service vulnerability in the web server's password mechanism.


The Rockwell Automation MicroLogix 1100 PLC integrated web server is a firmware version that is prior to FRN 10.0. It is, therefore, affected by a denial of service vulnerability due to a failure of the authentication mechanism to properly handle remote connections or commands. A remote attacker can exploit this, using a crafted request, to cause the product to enter a predefined fault mode, resulting in the device being reset to a factory-default state.

Note that Nessus has not attempted to exploit this issue but has instead relied only on the self-reported version number.


Upgrade to MicroLogix 1100 PLC firmware release version FRN 10.0 or later.

See Also

Plugin Details

Severity: Critical

ID: 84570

File Name: scada_rockwell_micrologix_1100_plc_dos_278864.nbin

Version: 1.68

Type: remote

Family: SCADA

Published: 7/7/2015

Updated: 7/19/2022

Risk Information


Risk Factor: Medium

Score: 5.9


Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

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

Vulnerability Information

CPE: cpe:/a:rockwellautomation:micrologix:1100, cpe:/h:rockwellautomation:ab_micrologix_controller_1100

Required KB Items: SCADA/Rockwell Automation MicroLogix 1100 PLC Web Server

Exploit Ease: No known exploits are available

Patch Publication Date: 5/17/2011

Vulnerability Publication Date: 5/17/2011

Reference Information

CVE: CVE-2009-3739

BID: 37827