Security update for postfix

Security update for postfix

Security update for postfix

Security update for postfix

Security update for postfix

Security update for postfix

Important: postfix security update

Important: postfix security update

Important: postfix security update

Moderate: postfix security update

The postfix.postinst script in the Debian GNU/Linux and Ubuntu postfix 2.5.5 package grants the postfix user write access to /var/spool/postfix/pid, which might allow local users to conduct symlink attacks that overwrite arbitrary files.

Postfix 2.4 before 2.4.9, 2.5 before 2.5.5, and 2.6 before 2.6-20080902, when used with the Linux 2.6 kernel, leaks epoll file descriptors during execution of "non-Postfix" commands, which allows local users to cause a denial of service (application slowdown or exit) via a crafted command, as demonstrated by a command in a .forward file.

Postfix 1.1.11 and earlier allows remote attackers to use Postfix to conduct "bounce scans" or DDos attacks of other hosts via an email address to the local host containing the target IP address and service name followed by a "!" string, which causes Postfix to attempt to use SMTP to communicate with the target on the associated port.

Postfix through 3.8.4 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages that appear to originate from the Postfix server, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports <LF>.<CR><LF> but some other popular e-mail servers do not. To prevent attack variants (by always disallowing <LF> without <CR>), a different solution is required: the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.

The address parser code in Postfix 1.1.12 and earlier allows remote attackers to cause a denial of service (lock) via (1) a malformed envelope address to a local host that would generate a bounce and contains the ".!" string in the MAIL FROM or Errors-To headers, which causes nqmgr to lock up, or (2) via a valid MAIL FROM with a RCPT TO containing a ".!" string, which causes an instance of the SMTP listener to lock up.

Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 sometimes allows a buffer over-read and process crash via an enhanced status code that lacks text after the third number.

The SMTP server in Postfix before 2.5.13, 2.6.x before 2.6.10, 2.7.x before 2.7.4, and 2.8.x before 2.8.3, when certain Cyrus SASL authentication methods are enabled, does not create a new server handle after client authentication fails, which allows remote attackers to cause a denial of service (heap memory corruption and daemon crash) or possibly execute arbitrary code via an invalid AUTH command with one method followed by an AUTH command with a different method.

Postfix before 2.3.15, 2.4 before 2.4.8, 2.5 before 2.5.4, and 2.6 before 2.6-20080814, when the operating system supports hard links to symlinks, allows local users to append e-mail messages to a file to which a root-owned symlink points, by creating a hard link to this symlink and then sending a message. NOTE: this can be leveraged to gain privileges if there is a symlink to an init script.

Postfix before 2.11.10, 3.0.x before 3.0.10, 3.1.x before 3.1.6, and 3.2.x before 3.2.2 might allow local users to gain privileges by leveraging undocumented functionality in Berkeley DB 2.x and later, related to reading settings from DB_CONFIG in the current directory.

** DISPUTED ** A certain Postfix 2.10.1-7 package could allow an attacker to send an email from an arbitrary-looking sender via a homoglyph attack, as demonstrated by the similarity of \xce\xbf to the 'o' character. This is potentially relevant when the /etc/postfix/sender_login feature is used, because a spoofed outbound message that uses a configured sender address is blocked with a "Sender address rejected: not logged in" error message, but a spoofed outbound message that uses a homoglyph of a configured sender address is not blocked. NOTE: some third parties argue that any missed blocking of spoofed outbound messages - except for exact matches to a sender address in the /etc/postfix/sender_login file - is outside the design goals of Postfix and thus cannot be considered a Postfix vulnerability.