[原文]The at program in IRIX 6.2 and NetBSD 1.3.2 and earlier allows local users to read portions of arbitrary files by submitting the file to at with the -f argument, which generates error messages that at sends to the user via e-mail.
A vulnerability exists in NetBSD version 1.3.2 and lower, and Silicon Graphics Inc's IRIX versions 6.2, 6.3, 6.4, 6.5 and 6.5.1. The at(1) program can be supplied with a -f flag, and an error is access validation can result in the mailing of portions of unreadable files to any user who can run at.
At uses seteuid to set the appropriate user id to run under. However, it incorrectly sets its real and effective uid to 0 prior to opening the filename passed to the -f flag. This allows any user to read any file on the filesystem.
$ at -f /etc/shadow now + 1 minute
This will mail back a portion of the shadow file to the user.