FTPS Cleartext Fallback Security Bypass

Medium Nessus Plugin ID 57272


The FTPS server on the remote host falls back to cleartext communication if SSL negotiations fail.


The remote FTPS server running on the remote host is affected by a security bypass vulnerability due to accepting unencrypted commands if SSL negotiations fail. A man-in-the-middle attacker can exploit this to intercept credentials and modify files.


If using Serv-U, upgrade to version or later. Otherwise, contact the vendor for a patch.

See Also


Plugin Details

Severity: Medium

ID: 57272

File Name: ftps_plaintext_fallback.nasl

Version: $Revision: 1.4 $

Type: remote

Family: FTP

Published: 2011/12/13

Modified: 2016/01/05

Dependencies: 10092

Risk Information

Risk Factor: Medium


Base Score: 5.8

Temporal Score: 4.8

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

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

Vulnerability Information

CPE: cpe:/a:serv-u:serv-u

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2011/11/29

Vulnerability Publication Date: 2011/11/29

Reference Information

BID: 50881

OSVDB: 77429