Executive brief
A vulnerability in the AppleShare IP Mail Server can allow a remote attacker to crash the email service. Because of how older Macintosh operating systems handle such errors, an attack often causes the entire physical server to freeze, requiring a manual reboot to restore operations. This disrupts email communications and any other services hosted on the affected machine.
Technical details
A classic buffer overflow vulnerability exists in the SMTP service of AppleShare IP Mail Server 5.0.3. The flaw is triggered when the server receives an excessively long string (approximately 500 bytes or more) following the SMTP 'HELO' command. An unauthenticated remote attacker can exploit this by connecting to the SMTP port and sending the malformed command. On affected MacOS 8.1 and earlier systems, this typically results in a kernel-level hang or 'lock up,' necessitating a physical reboot of the hardware. While primarily a denial-of-service vector, the nature of the overflow suggests potential for arbitrary code execution.
Affected products
- Apple AppleShare Mail Server 5.0.3 on MacOS 8.1 and earlier
Timeline
- 1998-04-08: disclosed: Initial disclosure on Bugtraq mailing list
- 1998-04-08: advisory: NVD publication date