Bài giảng "An toàn dịch vụ ở xa" cung cấp đến các bạn với những kiến thức về tổng quan về an ninh mạng; một số phương thức tấn công mạng phổ biến; biện pháp đảm bảo an ninh mạng; mạng riêng ảo VPN (Virtual Private Networks). Mời các bạn cùng tham khảo. | An Toàn Dịch Vụ Ở Xa Overview Remote information services provide system user and network details over IP. Such services can be probed to collate username listings and details of trusted networks and hosts and in some cases compromise systems directly The systat and netstat services are interesting because current network and system information can be found easily by connecting to the services using telnet 2 FTP File Transfer Protocol FTP provides remote file system access usually for maintenance of web applications FTP services are vulnerable to the following classes of attack Brute-force password grinding Anonymous browsing and exploitation of software defects Authenticated exploitation of vulnerabilities requiring certain privileges 3 Fingerprinting FTP Services Nmap performs network service and OS fingerprinting via the -A flag -A flag invokes the ftp-anon script among others which tests for anonymous access and returns the server directory structure upon authenticating. 4 For example FTP service fingerprinting using Nmap 5 Known FTP Vulnerabilities 1 2 Popular FTP servers include the Microsoft IIS FTP Server ProFTPD and Pure-FTPd 6 Known FTP Vulnerabilities 2 2 To evaluate publicly available exploit scripts use the searchsploit utility within Kali Linux 7 TFTP TFTP Trivial File Transfer Protocol uses UDP port 69 and requires no authentication clients read from and write to servers using the datagram format outlined in RFC 1350. Within large internal networks however TFTP is used to serve configuration files and ROM images to VoIP handsets and other devices. TFTP servers are exploited via the following attack classes Obtaining material from the server . configuration files containing secrets Bypassing controls to overwrite data on the server . replacing a ROM image Executing code via an overflow or memory corruption flaw 8 TFTP brute-force and file recovery 1 2 9 TFTP brute-force and file recovery 2 2 Many TFTP server configurations also permit arbitrary
