Progeny Security Advisory: Vulnerabilities in FTP daemonsApr 27, 2001, 02:13 (0 Talkback[s])
From: Progeny Security Team <firstname.lastname@example.org> Subject: PROGENY-SA-2001-09: Vulnerabilities in FTP daemons Date: 26 Apr 2001 18:31:40 -0500
PROGENY SERVICE NETWORK -- SECURITY ADVISORY PROGENY-SA-2001-09 Synopsis: Vulnerabilities in FTP daemons Software: Some FTP servers (See PACKAGE SUMMARY below) History: 2000-12-04 Off-by-one OpenBSD vulnerability announced 2000-12-05 Debian bsd-ftpd fixed in unstable 2000-12-07 Debian ftpd fixed in unstable 2000-12-18 OpenBSD Security advisory for off-by-one 2001-04-09 NAI COVERT Labs advisory for globbing 2001-04-17 FreeBSD advisory for globbing 2001-04-26 Progeny Service Network advisory and fix for both issues Credits: PGP Security/NAI COVERT Labs John McDonald
This advisory discusses issues that could impact multiple FTP daemons from multiple sources and vendors. All related and similar software in Progeny Debian is summarized here:
Package Status Fix
atftpd NOT vulnerable n/a bsd-ftpd IS vulnerable prior to 0.3.2-7 Install bsd-ftpd 0.3.2-7 ftpd IS vulnerable prior to 0.17-2 Install ftpd 0.17-3 muddleftpd NOT vulnerable n/a proftpd NOT vulnerable n/a pyftpd NOT vulnerable n/a tftpd NOT vulnerable n/a wu-ftpd NOT vulnerable n/a
Recently, several bugs have been discovered in various FTP servers. If your Progeny Debian system runs either bsd-ftpd or ftpd, you may be vulnerable to a remote security bug.
Three problems exist with some FTP daemons on certain platforms:
Unauthorized persons may be able to exploit this problem to gain root access.
The third problem above is the one of potential concern to Progeny Debian users. This issue was first reported against OpenBSD and a public exploit exists for that platform. To date, we are not aware of any exploit or incident related to this bug on a Linux platform.
An attacker will only be able to exploit the problem if writes to the FTP server are permitted. Therefore, we believe anonymous FTP sites that carry no "incoming" directories are not vulnerable to this attack. However, we do suggest that anyone running ftpd or bsd-ftpd upgrade as soon as possible.
To determine whether you have one of the affected packages, run the following command:
# dpkg -l '*ftpd'
SOLUTION (See also: UPDATING VIA APT-GET)
Upgrade to a fixed version of ftpd or bsd-ftpd. ftpd 0.17-3 and bsd-ftpd 0.3.2-7 both contain fixes for the problem documented in this advisory.
UPDATING VIA APT-GET (RECOMMENDED)
deb http://archive.progeny.com/progeny updates/newton/
2. Update your cache of available packages for apt(8).
# apt-get update
3. Using apt(8), install the new package. apt(8) will download the update, verify its integrity with md5, and then install the package on your system with dpkg(8).
# apt-get install ftpd
UPDATING VIA DPKG
MD5 Checksum Filename -------------------------------- ------------------------------------- 5a8d2bbccc1612dd18c6478e5df63ebb ftp bsd-ftpd_0.3.2-7_i386.deb a272fc4b83848144c7fb88b8254d9d5e ftp ftpd_0.17-3_i386.deb
You need only download the one package that is relevant to your situation. In the examples that follow, we will illustrate with ftpd.
2. Use the md5sum command on the retrieved files to verify that they match the md5sum provided in this advisory:
# md5sum ftp ftpd_0.17-3_i386.deb
3. Then install the replacement package(s) using the dpkg command.
# dpkg --install ftp ftpd_0.17-3_i386.deb
If you prefer not to upgrade your ftpd or bsd-ftpd package, you may instead install one of the other non-vulnerable FTP servers listed above. Or, you may remove the packages from your system with one of the following:
# dpkg --remove ftpd
NAI Advisory: http://www.pgp.com/research/covert/advisories/048.asp
FreeBSD Globbing Advisory: http://archive.progeny.com/FreeBSD/CERT/advisories/FreeBSD-SA-01:33.ftpd-glob.asc
SecurityFocus summary: http://www.securityfocus.com/bid/2548
OpenBSD Advisory: http://www.openbsd.org/advisories/ftpd_replydirname.txt
OpenBSD Bug Report: http://www.geocrawler.com/lists/3/OpenBSD/254/75/4767480/
Debian bsd-ftpd bug report: http://bugs.debian.org/78786
Debian ftpd bug report: http://bugs.debian.org/78973
Progeny advisories can be found at http://www.progeny.com/security/.
pub 1024D/F92D4D1F 2001-04-04 Progeny Security Team <email@example.com>