vsftpd vsf_filename_passes_filter Function Denial of Service

Medium Nessus Plugin ID 52704

Synopsis

The remote FTP server is prone to a denial of service attack.

Description

According to its self-reported version number, the instance of vsftpd listening on the remote server is earlier than 2.3.3 and, as such, may be affected by a denial of service vulnerability.

An error exists in the function 'vsf_filename_passes_filter()' in 'ls.c' that allows resource intensive glob expressions to be processed with the 'STAT' command. Using numerous IP addresses to bypass an FTP-sessions-per-IP-address limit, a remote attacker can carry out a denial of service attack.

Note that Nessus did not actually test for the flaw but instead has relied on the version in vsftpd's banner.

Solution

Update to vsftpd 2.3.4 or later. [While version 2.3.3 actually addresses this issue, 2.3.4 was released the same day to address a problem compiling the earlier version.]

See Also

https://downloads.securityfocus.com/vulnerabilities/exploits/46617.c

ftp://vsftpd.beasts.org/users/cevans/untar/vsftpd-2.3.3/Changelog

https://seclists.org/bugtraq/2011/Mar/9

Plugin Details

Severity: Medium

ID: 52704

File Name: vsftpd_2_3_3.nasl

Version: 1.9

Type: remote

Family: FTP

Published: 2011/03/17

Modified: 2018/11/15

Dependencies: 52703

Risk Information

Risk Factor: Medium

CVSS v2.0

Base Score: 4

Temporal Score: 3.1

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

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

Vulnerability Information

Required KB Items: ftp/vsftpd, Settings/ParanoidReport

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2011/02/15

Vulnerability Publication Date: 2011/03/01

Reference Information

CVE: CVE-2011-0762

BID: 46617

EDB-ID: 16270