Joined: 25 Feb 2003
Location: Essen, Germany
|Posted: Tue May 25, 2004 5:53 pm Post subject: [ GLSA 200405-19 ] Opera telnet URI handler file creation/tr
|Gentoo Linux Security Advisory
Title: Opera telnet URI handler file creation/truncation vulnerability (GLSA 200405-19)
Date: May 25, 2004
Updated: December 30, 2007
A vulnerability exists in Opera's telnet URI handler that may allow a remote attacker to overwrite arbitrary files.
Opera is a multi-platform web browser.
Vulnerable: < 7.50_beta1
Unaffected: >= 7.50_beta1
Architectures: All supported architectures
The telnet URI handler in Opera does not check for leading '-' characters in the host name. Consequently, a maliciously-crafted telnet:// link may be able to pass options to the telnet program itself. One example would be the following: telnet://-nMyFile If MyFile exists in the user's home directory and the user clicking on the link has write permissions to it, the contents of the file will be overwritten with the output of the telnet trace information. If MyFile does not exist, the file will be created in the user's home directory.
This exploit has two possible impacts. First, it may create new files in the user's home directory. Second, and far more serious, it may overwrite existing files that the user has write permissions to. An attacker with some knowledge of a user's home directory might be able to destroy important files stored within.
Disable the telnet URI handler from within Opera.
All Opera users are encouraged to upgrade to the latest version of the program:
|# emerge sync
# emerge -pv ">=www-client/opera-7.50_beta1"
# emerge ">=www-client/opera-7.50_beta1"
iDEFENSE Security Advisory 05.12.04
Last edited by GLSA on Mon Dec 31, 2007 4:16 am; edited 3 times in total