Fetchmail: Denial of Service and password disclosure

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200701-13 / fetchmail
Release Date	January 22, 2007
Latest Revision	January 22, 2007: 01
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-mail/fetchmail	< 6.3.6	>= 6.3.6	All supported architectures

Related bugreports: #160463

Synopsis

Fetchmail has been found to have numerous vulnerabilities allowing for Denial of Service and password disclosure.

2. Impact Information

Background

Fetchmail is a remote mail retrieval and forwarding utility.

Description

Neil Hoggarth has discovered that when delivering messages to a message delivery agent by means of the "mda" option, Fetchmail passes a NULL pointer to the ferror() and fflush() functions when refusing a message. Isaac Wilcox has discovered numerous means of plain-text password disclosure due to errors in secure connection establishment.

Impact

An attacker could deliver a message via Fetchmail to a message delivery agent configured to refuse the message, and crash the Fetchmail process. SMTP and LMTP delivery modes are not affected by this vulnerability. An attacker could also perform a Man-in-the-Middle attack, and obtain plain-text authentication credentials of users connecting to a Fetchmail process.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All fetchmail users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-mail/fetchmail-6.3.6"

4. References

Page updated January 22, 2007

Summary: This is a Gentoo Linux Security Advisory

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