PHPShell v2.4 Session Fixation

Credit: hyp3rlinx
Risk: Medium
Local: No
Remote: Yes

[+] Credits: John Page AKA hyp3rlinx [+] Website: [+] Source: [+] ISR: ApparitionSec Vendor: ================================== Product: ============== PHPShell v2.4 Vulnerability Type: =================== Session Fixation CVE Reference: ============== N/A Security Issue: ================ PHPShell does not regenerate the Session ID upon authentication, this can potentially allow remote attackers to access parts of the application using only a valid PHPSESSID if PHP.INI setting for session.use_only_cookies=0. Since an existing XSS vulnerability exists in PHPShell "" the risk is increased if an authenticated user clicks an attacker supplied link and the attacker finds way to access or set the victims Cookie. In 'phpshell.php' line 153 we see call to PHP function session_start(); After user authentication no call to "session_regenerate_id()" is made leaving the authenticated session id same as pre-auth session id. However, "session.use_only_cookies=1" is default since PHP 4.3.0, so to exploit it would require that PHP.INI is set to session.use_only_cookies=0 on the victims system. When accessing the application using the session fixation flaw and attempting to run system command the application luckily redirects to login form. However, if a victim is actively changing directorys, reading files etc... attackers may still be able to read current directory and files open in the victims PHPShell console window. Exploit/POC: ============= 1) Login to PHPShell run commands to CD to Windows directory and run DIR command etc, then find and copy the PHPSESSID Cookie 2) Open a second browser (InternetExplorer) and access the application cleanly for first time using the PHPSESSID in URL. e.g. http://VICTIM-IP/phpshell-2.4/phpshell.php?PHPSESSID=<STOLEN-SESSION-ID> You should see what the authenticated victim now sees... e.g. Current Working Directory: Change to subdirectory: 07/13/2009 08:51 PM 24,576 Microsoft.MediaCenter.iTv.Hosting.dll 11/20/2010 10:24 PM 147,968 Microsoft.MediaCenter.iTV.Media.dll 07/13/2009 08:52 PM 45,056 Microsoft.MediaCenter.ITVVM.dll 11/20/2010 10:24 PM 56,320 Microsoft.MediaCenter.Mheg.dll 11/20/2010 10:24 PM 114,688 Microsoft.MediaCenter.Playback.dll 11/20/2010 10:24 PM 1,572,864 Microsoft.MediaCenter.Shell.dll 11/20/2010 10:24 PM 241,664 Microsoft.MediaCenter.Sports.dll 11/20/2010 10:24 PM 327,168 Microsoft.MediaCenter.TV.Tuners.Interop.dll 11/20/2010 10:24 PM 2,596,864 Microsoft.MediaCenter.UI.dll 10/29/2011 12:23 AM 465,920 mstvcapn.dll 11/20/2010 10:24 PM 88,576 NetBridge.dll 07/13/2009 08:51 PM 106,496 RegisterMCEApp.exe 06/10/2009 04:04 PM 129,528 segmcr.ttf etc... Network Access: =============== Remote Severity: ========= Medium Disclosure Timeline: ============================= Vendor Notification: No reply Also, the INSTALL file "Bugs? Comments? Tracker System link" is HTTP 404 February 18, 2017 : Public Disclosure [+] Disclaimer The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. All content (c) HYP3RLINX - ApparitionSec


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