Apple security update 2006-004 is now available

Security Update 2006-004 can be downloaded and installed using Software Update, or from Apple Downloads.

Security Update 2006-004 is recommended for all users and improves the security of the following components:

  • AFP Server
  • Bluetooth
  • Bom
  • DHCP
  • dyld
  • fetchmail
  • gnuzip
  • ImageIO
  • LaunchServices
  • OpenSSH
  • telnet
  • WebKit

Interesting to mention are:


A stack buffer overflow exists in bootpd’s request processing. By carefully crafting a malicious BOOTP request, a remote attacker may be able to trigger the overflow and cause arbitrary code execution with the privileges of the system. Note that bootpd is not enabled by default in Mac OS X, and must be manually configured in order to be enabled. This update addresses the issue by performing additional bounds checking.


Several issues in the fetchmail utility were discovered. The most serious issue could lead to arbitrary code execution when fetching mail from a malicious POP3 mail server. All issues are described at the fetchmail website ( This update addresses the issues by updating fetchmail to version 6.3.4. In addition, fetchmail is no longer distributed as a privileged utility.


Attempting to log in to an OpenSSH server (“Remote Login”) using a nonexistent account causes the authentication process to hang. An attacker can exploit this behavior to detect the existence of a particular account. A large number of such attempts may lead to a denial of service. This update addresses the issue by properly handling attempted logins by nonexistent users. This issue does not affect systems prior to Mac OS X v10.4.

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