vsftpd Smiley Face Backdoor

high Nessus Plugin ID 55523
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The remote FTP server contains a backdoor, allowing execution of arbitrary code.


The version of vsftpd running on the remote host has been compiled with a backdoor. Attempting to login with a username containing :) (a smiley face) triggers the backdoor, which results in a shell listening on TCP port 6200. The shell stops listening after a client connects to and disconnects from it.

An unauthenticated, remote attacker could exploit this to execute arbitrary code as root.


Validate and recompile a legitimate copy of the source code.

See Also



Plugin Details

Severity: High

ID: 55523

File Name: vsftpd_smileyface_backdoor.nasl

Version: 1.9

Type: remote

Family: FTP

Published: 7/6/2011

Updated: 11/15/2018

Dependencies: ftpserver_detect_type_nd_version.nasl, find_service2.nasl

Risk Information


Risk Factor: Critical

Base Score: 10

Temporal Score: 8.3

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

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


Risk Factor: High

Base Score: 8.8

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

Vulnerability Information

Excluded KB Items: global_settings/supplied_logins_only

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/3/2011

Vulnerability Publication Date: 7/3/2011

Exploitable With

Metasploit (VSFTPD v2.3.4 Backdoor Command Execution)

Reference Information

BID: 48539

EDB-ID: 17491