auction.weaver.txt

`File deletion and other bugs in Auction Weaver LITE 1.0 - 1.04  
--------------------------------------------------------------  
  
Title: File deletion and other bugs in Auction Weaver LITE 1.0 - 1.04  
Author: Steve Christey ([email protected])  
Date Published: October 16, 2000  
  
Product Name: Auction Weaver LITE  
Affected Versions: 1.0 through 1.04  
Affected Operating Systems: Unix and Windows NT  
Product URL: http://www.cgiscriptcenter.com/awl/  
  
Vendor Name: CGI Script Center  
Vendor URL: http://www.cgiscriptcenter.com/  
Vendor Email: [email protected]  
  
Impact: delete and read arbitrary files  
Remotely Exploitable: yes  
Locally Exploitable: no  
  
Patch Available: yes  
Patched Version: Auction Weaver 1.05  
Patch URL: http://www.cgiscriptcenter.com/awl/  
  
Bugtraq ID's: 1782, 1783  
http://www.securityfocus.com/bid/1782  
http://www.securityfocus.com/bid/1783  
  
CVE Candidate Numbers: CAN-2000-0810, CAN-2000-0811  
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2000-0810  
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2000-0811  
  
  
Description  
-----------  
  
Auction Weaver LITE is a CGI program written in Perl. It allows users  
to create and host auctions on their web site.  
  
Auction Weaver LITE 1.0 through 1.04 was discovered to contain several  
vulnerabilities that allow remote attackers to create, read, or delete  
arbitrary files with the privileges of the Auction Weaver process.  
These vulnerabilities are different than the ones described by  
Meliksah Ozoral and teleh0r in several Bugtraq posts during August  
2000 [see references below]. All of the vulnerabilities are commonly  
found in CGI scripting programs.  
  
These vulnerabilities were successfully exploited using a default  
installation of Auction Weaver on a Solaris 7 box. However, all  
platforms are vulnerable.  
  
The vendor has been notified and a patch is available.  
  
  
Solution  
--------  
  
Auction Weaver 1.05 fixes all of the vulnerabilities described in this  
advisory. Upgrade to Auction Weaver 1.05 at:  
  
http://www.cgiscriptcenter.com/awl/  
  
A complete workaround is not possible for the arbitrary file deletion  
problem, so users should upgrade to version 1.05.  
  
  
Additional Vulnerability Details  
--------------------------------  
  
These vulnerabilities were discovered while attempting to determine  
whether CGI Script Center had patched the previously announced  
vulnerabilities. (While some acknowledgement was posted on the  
vendor's web site, it did not provide sufficient details to be certain  
that all of the identified problems had been fixed).  
  
The Common Vulnerabilities and Exposures (CVE) project has assigned  
unique names to each of these vulnerabilities. They are candidates  
for inclusion in the CVE list, which standardizes names for security  
problems. See http://cve.mitre.org/  
  
The Security Focus VulnHelp service has also assigned Bugtraq ID's to  
these vulnerabilities. See http://www.securityfocus.com/vdb/  
  
1) File/directory deletion with malicious form field names containing ..  
CVE candidate: CAN-2000-0810  
Bugtraq ID: 1782  
  
In Auction Weaver 1.0 through 1.04, a remote attacker can delete  
arbitrary directories, and files within them, with the privileges of  
the Auction Weaver process. This vulnerability is due to a lack of  
sanity checking of the names of the form fields. Due to the nature  
of the bug, files can be deleted outside of the web document root  
using .. notation. Even if the filenames were properly cleansed of  
.. problems, however, non-administrators would still be able to  
delete auction information, because the vulnerable function is not  
password protected.  
  
The extent of this vulnerability is slightly mitigated by the fact  
that if the targeted directory contains subdirectories, the script  
may fail once it attempts to delete that subdirectory. However, it  
may have deleted other files before reaching that subdirectory.  
  
2) Arbitrary file reading and creation with .. in username and bidfile  
CVE candidate: CAN-2000-0811  
Bugtraq ID: 1783  
  
In Auction Weaver 1.0 through 1.04, a remote attacker can read and  
create arbitrary files in arbitrary directories with the same  
privileges as the Auction Weaver process. The attacker can not  
fully control the contents of the file.  
  
The vulnerable script does not properly cleanse two form fields  
(username and bidfile) whose values are later used in constructing  
file pathnames. These form fields are different than those  
described in previous Bugtraq posts, but it is the same kind of  
vulnerability. An attacker can insert a .. into the field's value  
to access files outide of the data directory.  
  
The scope of the problem would be limited to file names with .dat  
extensions, except the program is written in Perl and does not  
filter out null characters. Thus the attacker can insert a null  
character at the end of the filename as specified in the form,  
effectively bypassing the .dat extension that is later appended to  
the filename.  
  
3) Incomplete patching of catdir and fromfile .. vulnerabilities  
CVE candidate: CAN-2000-0686 (already assigned)  
Bugtraq ID: 1630  
  
Auction Weaver 1.04 does not completely fix the .. vulnerabilities  
in the "catdir" and "fromfile" form fields, which was described by  
Meliksah Ozoral in a Bugtraq post on August 23, 2000 [1]. As  
originally described, these fields allowed file reading; however,  
they also allow file deletion.  
  
In version 1.04, the regular expression for removing ".." from  
filenames is not properly specified. Only files in the parent of  
the data directory can be read or deleted. However, in the default  
installation of Auction Weaver, the parent directory includes the  
server script itself. The script itself could be deleted, or the  
administrative password could be read from it.  
  
  
References  
----------  
  
The following vulnerabilities were discovered in earlier versions of  
Auction Weaver. They are listed here to distinguish them from the new  
vulnerabilities discussed in this advisory.  
  
[1] Directory traversal in version 1.02 via catdir form field.  
  
Bugtraq post by Meliksah Ozoral on August 23, 2000, titled  
"Auction WeaverT LITE 1.0" (subject is also listed as  
"=?iso-8859-9?Q?Auction_WeaverT_LITE_1.0?=" in some archives)  
  
URL: http://www.securityfocus.com/archive/1/78458  
  
Bugtraq ID: 1630  
CVE candidate name: CAN-2000-0690  
  
[2] Execute commands with shell metacharacters in fromfile form field  
in version 1.02.  
  
Bugtraq post by teleh0r on August 30, 2000, titled "More problems  
with Auction Weaver & CGI Script Center."  
  
URL: http://www.securityfocus.com/archive/1/79452  
  
Bugtraq ID: 1645  
CVE candidate name: CAN-2000-0687  
  
  
Disclosure Process  
------------------  
  
These vulnerabilities were disclosed to the vendor, and to the public,  
with guidance from Rain Forest Puppy's Issue disclosure policy (aka  
RFPolicy) at http://www.wiretrip.net/rfp/policy.html. In addition,  
this advisory follows emerging best practices for the responsible  
disclosure of new vulnerability information.  
  
1) VENDOR NOTIFICATION  
  
Email was sent to the vendor at the suggested email addresses  
referenced in RFPolicy, i.e.: securityalert, secure, security,  
support, and [email protected]. The email provided all  
known details of the vulnerabilities, including exploits and fixes.  
A brief alert was also submitted to the online contact web page.  
  
The subject header included the phrase "Serious security  
vulnerabilities."  
  
The email included contact information such as name, title,  
organization, and phone number.  
  
Guidance was provided to the vendor to ensure that the  
vulnerabilities were properly patched.  
  
2) PUBLIC NOTIFICATION  
  
Public announcement of the vulnerabilities was delayed until the  
vendor had a patch available and its customers were notified.  
  
This advisory includes commonly used identifiers (Bugtraq ID's and  
CVE candidate names) to support cross-referencing and to  
distinguish these vulnerabilities from others.  
  
The Security Focus VulnHelp service was consulted to obtain the  
Bugtraq ID's. For more information or assistance in drafting  
advisories, please email [email protected].  
  
3) LEVEL OF DETAIL  
  
Sufficient technical details are provided in this advisory so that  
security researchers and system administrators can understand the  
nature of the problems and distinguish them from similar problems.  
Exploit code is not included with this advisory. However, all  
exploit materials were provided to the vendor.  
  
  
Event Log  
---------  
  
Sep 16, 2000:  
- initial discovery  
- notified vendor  
- email to [email protected] and others  
- short post to the online contact form  
  
Sep 18, 2000:  
- Vendor responded from both contact points (on the next business  
day). Additional details provided to vendor  
- Vendor disabled downloads for the vulnerable software  
  
Sep 20, 2000:  
- Sent email to vendor requesting a status update  
- Received a response that the vendor is still working on fixes  
  
Sep 21, 2000:  
- Vendor email that problems have been fixed, requested clarification  
- Sent clarification  
  
Sep 22, 2000:  
- Vendor submitted new version for review  
- Sent additional feedback  
  
Sep 23, 2000:  
- Vendor completed fixes, sent for final review  
  
Sep 25, 2000:  
- Final review complete  
- Vendor released new version  
- Advisory written and sent to vendor for review  
- Obtained CVE candidate names for advisory  
  
Sep 26, 2000:  
- Advisory approved by vendor  
  
Oct 5, 2000:  
- Advisory submitted to VulnHelp for review and Bugtraq ID's  
  
Oct 12, 2000:  
- Bugtraq ID's obtained from VulnHelp  
  
Oct 16, 2000:  
- Advisory submitted to Bugtraq, NTBugtraq, and CERT/CC  
`