others edit pages in your wiki, then some possible security issues do need
to be kept in mind.
-[[toc levels=2]]
+[[!toc levels=2]]
----
Of course nobody else seems to worry about this in other wikis, so should we?
-Currently only people with direct commit access can upload such files
+People with direct commit access can upload such files
(and if you wanted to you could block that with a pre-commit hook).
-Users with only web commit access are limited to editing pages as ikiwiki
-doesn't support file uploads from browsers (yet), so they can't exploit
-this.
+
+The attachments plugin is not enabled by default. If you choose to
+enable it, you should make use of its powerful abilities to filter allowed
+types of attachments, and only let trusted users upload.
+
+It is possible to embed an image in a page edited over the web, by using
+`img src="data:image/png;"`. Ikiwiki's htmlscrubber only allows `data:`
+urls to be used for `image/*` mime types. It's possible that some broken
+browser might ignore the mime type and if the data provided is not an
+image, instead run it as javascript, or something evil like that. Hopefully
+not many browsers are that broken.
## multiple accessors of wiki directory
## setup files
-Setup files are not safe to keep in subversion with the rest of the wiki.
-Just don't do it. [[ikiwiki.setup]] is *not* used as the setup file for
-this wiki, BTW.
+Setup files are not safe to keep in the same revision control repository
+with the rest of the wiki. Just don't do it.
## page locking can be bypassed via direct commits
A locked page can only be edited on the web by an admin, but anyone who is
allowed to commit directly to the repository can bypass this. This is by
design, although a pre-commit hook could be used to prevent editing of
-locked pages when using subversion, if you really need to.
+locked pages, if you really need to.
## web server attacks
## suid wrappers
-ikiwiki --wrapper is intended to generate a wrapper program that
+`ikiwiki --wrapper` is intended to generate a wrapper program that
runs ikiwiki to update a given wiki. The wrapper can in turn be made suid,
for example to be used in a [[post-commit]] hook by people who cannot write
to the html pages, etc.
## shell exploits
ikiwiki does not expose untrusted data to the shell. In fact it doesn't use
-system() at all, and the only use of backticks is on data supplied by the
-wiki admin and untainted filenames. And it runs with taint checks on of
-course..
+`system(3)` at all, and the only use of backticks is on data supplied by the
+wiki admin and untainted filenames.
+
+Ikiwiki was developed and used for a long time with perl's taint checking
+turned on as a second layer of defense against shell and other exploits. Due
+to a strange [bug](http://bugs.debian.org/411786) in perl, taint checking
+is currently disabled for production builds of ikiwiki.
## cgi data security
## cgi password security
-Login to the wiki involves sending a password in cleartext over the net.
-Cracking the password only allows editing the wiki as that user though.
-If you care, you can use https, I suppose. If you do use https either for
-all of the wiki, or just the cgi access, then consider using the sslcookie
-option.
+Login to the wiki using [[plugins/passwordauth]] involves sending a password
+in cleartext over the net. Cracking the password only allows editing the wiki
+as that user though. If you care, you can use https, I suppose. If you do use
+https either for all of the wiki, or just the cgi access, then consider using
+the sslcookie option. Using [[plugins/openid]] is a potentially better option.
## XSS holes in CGI output
-ikiwiki has not yet been audited to ensure that all cgi script input/output
+ikiwiki has been audited to ensure that all cgi script input/output
is sanitised to prevent XSS attacks. For example, a user can't register
with a username containing html code (anymore).
notice.
This security hole was discovered on 26 November 2007 and fixed the same
-da with the release of ikiwiki 2.14. I recommend upgrading to this version
+day with the release of ikiwiki 2.14. I recommend upgrading to this version
if your wiki can be committed to by third parties. Alternatively, don't use
a trailing slash in the srcdir, and avoid the (unusual) configurations that
allow the security hole to be exploited.
+
+## javascript insertion via uris
+
+The htmlscrubber did not block javascript in uris. This was fixed by adding
+a whitelist of valid uri types, which does not include javascript.
+([[!cve CVE-2008-0809]]) Some urls specifyable by the meta plugin could also
+theoretically have been used to inject javascript; this was also blocked
+([[!cve CVE-2008-0808]]).
+
+This hole was discovered on 10 February 2008 and fixed the same day
+with the release of ikiwiki 2.31.1. (And a few subsequent versions..)
+A fix was also backported to Debian etch, as version 1.33.4. I recommend
+upgrading to one of these versions if your wiki can be edited by third
+parties.
+
+## Cross Site Request Forging
+
+Cross Site Request Forging could be used to constuct a link that would
+change a logged-in user's password or other preferences if they clicked on
+the link. It could also be used to construct a link that would cause a wiki
+page to be modified by a logged-in user. ([[!cve CVE-2008-0165]])
+
+These holes were discovered on 10 April 2008 and fixed the same day with
+the release of ikiwiki 2.42. A fix was also backported to Debian etch, as
+version 1.33.5. I recommend upgrading to one of these versions.
+
+## Cleartext passwords
+
+Until version 2.48, ikiwiki stored passwords in cleartext in the `userdb`.
+That risks exposing all users' passwords if the file is somehow exposed. To
+pre-emtively guard against that, current versions of ikiwiki store password
+hashes (using Eksblowfish).
+
+If you use the [[plugins/passwordauth]] plugin, I recommend upgrading to
+ikiwiki 2.48, installing the [[!cpan Authen::Passphrase]] perl module, and running
+`ikiwiki-transition hashpassword` to replace all existing cleartext passwords
+with strong blowfish hashes.
+
+You might also consider changing to [[plugins/openid]], which does not
+require ikiwiki deal with passwords at all, and does not involve users sending
+passwords in cleartext over the net to log in, either.
+
+## Empty password security hole
+
+This hole allowed ikiwiki to accept logins using empty passwords, to openid
+accounts that didn't use a password. It was introduced in version 1.34, and
+fixed in version 2.48. The [bug](http://bugs.debian.org/483770) was
+discovered on 30 May 2008 and fixed the same day. ([[!cve CVE-2008-0169]])
+
+I recommend upgrading to 2.48 immediatly if your wiki allows both password
+and openid logins.
+
+## Malformed UTF-8 DOS
+
+Feeding ikiwiki page sources containing certian forms of malformed UTF-8
+can cause it to crash. This can potentially be used for a denial of service
+attack.
+
+intrigeri discovered this problem on 12 Nov 2008 and a patch put in place
+later that day, in version 2.70. The fix was backported to testing as version
+2.53.3, and to stable as version 1.33.7.