Some versions of Gnu Privacy Guard (GPG) contain a format-string vulnerability from improper handling of filenames when decrypting files.
GPG is an OpenPGP-compliant alternative to PGP to protect electronic communications using public-key cryptography. Versions of GPG prior to 1.0.6 contain a format-string vulnerability.
The GPG source includes a function named tty_printf(), which expects as parameters -- much like the standard C library function printf() -- a format string followed by data values as indicated in the format string. The do_get() function in file util/ttyio.c of the GPG source code makes a call to tty_printf(), passing the filename as the format string instead of passing a constant format string followed by a pointer to the filename.
Attackers can craft a filename for an encrypted file that will cause GPG to execute arbitrary code when the file is decrypted by the recipient, with the privileges of the recipient user.
Upgrade GPG to version 1.0.6, available from:
Until a patch can be applied, do not decrypt messages from untrusted sources with GPG.
Free Software Foundation
Thanks to fish stiqz for reporting this vulnerability.
This document was written by Shawn Van Ittersum.
|Date First Published:||2002-03-29|
|Date Last Updated:||2002-03-29 22:59 UTC|