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Keamanan Komputer Nama : Hartono Npm : 13411251 Kelas : 4ib03 Tugas : KEAMANAN KOMPUTER Keamanan komputer atau dalam Bahasa Inggris computer security atau dikenal juga dengan sebutan cybersecurity atau IT security adalah keamanan infromasi yang diaplikasikan kepada komputer dan jaringannya. Computer security atau keamanan komputer bertujuan membantu user agar dapat mencegah penipuan atau mendeteksi adanya usaha penipuan di sebuah sistem yang berbasis informasi. Informasinya sendiri memiliki arti non fisik. Keamanan komputer adalah suatu cabang teknologi yang dikenal dengan nama keamanan informasi yang diterapkan pada komputer. Sasaran keamanan komputer antara lain adalah sebagai perlindungan informasi terhadap pencurian atau korupsi, atau pemeliharaan ketersediaan, seperti dijabarkan dalam kebijakan keamanan. Sistem keamanan komputer merupakan sebuah upaya yang dilakukan untuk mengamankan kinerja dan proses komputer. Penerapan computer security dalam kehidupan sehari-hari berguna sebagai penjaga sumber daya sistem agar tidak digunakan, modifikasi, interupsi, dan diganggu oleh orang yang tidak berwenang. Keamanan bisa diindentifikasikan dalam masalah teknis, manajerial, legalitas, dan politis. computer security akan membahas 2 hal penting yaitu Ancaman/Threats dan Kelemahan sistem/vulnerabillity. Keamanan komputer memberikan persyaratan terhadap komputer yang berbeda dari kebanyakan persyaratan sistem karena sering kali berbentuk pembatasan terhadap apa yang tidak boleh dilakukan komputer. Ini membuat keamanan komputer menjadi lebih menantang karena sudah cukup sulit untuk membuat program komputer melakukan segala apa yang sudah dirancang untuk dilakukan dengan benar. Persyaratan negatif juga sukar untuk dipenuhi dan membutuhkan pengujian mendalam untuk verifikasinya, yang tidak praktis bagi kebanyakan program komputer. Keamanan komputer memberikan strategi teknis untuk mengubah persyaratan negatif menjadi aturan positif yang dapat ditegakkan. Pendekatan yang umum dilakukan untuk meningkatkan keamanan komputer antara lain adalah dengan membatasi akses fisik terhadap komputer, menerapkan mekanisme pada perangkat keras dan sistem operasi untuk keamanan komputer, serta membuat strategi pemrograman untuk menghasilkan program komputer yang dapat diandalkan. -Lingkup Keamanan Komputer Lingkup keamanan adalah sisi-sisi jangkauan kemanan komputer yang bisa dilakukan. Pada prinsipnya pengamanan sistem komputer mencakup empat hal, yaitu: • Pengamanan secara fisik Komputer secara fisik adalah wujud komputer yang bisa dilihat dan diraba, seperti monitor, CPU, keyboard, dan lain-lain. Jika komputer memang perlu untuk diamankan karena fungsi dan data di dalamnya penting, maka pengamanan secra fisik dapat dilakukan dengan menempatkannya pada tempat atau lokasi yang mudah diawasi dan dikendalikan, pada ruangan tertentu yang dapat dikunci, dan sulit dijangkau orang lain, sehingga tidak ada komponen yang hilang. Kebersihan ruangan juga menjadi faktor pengaman fisik, hindari ruangan yang kotor, lembab, dan panas. Usahakan ruangan tetap dingin jika perlu be-AC tetapi tidak lembab. • Pengamanan Akses Ini dilakukan untuk PC yang menggunakan sistem operasi logging(penguncian) dan sistem operasi jaringan. Ini dilakukan untuk mengantisipasi kejadian yan sifatnya disengaja atau tidak disengaja, seperti kelalaian atau keteledoran user yang seringkali meninggalkan komputer dalam keadaan masih menyala, atau jika berada pada jaringan komputer tersebut masih berada dalam logon user. Keteledoran semacam ini dapat mengakibatkan pihak lain dapat mengakses beberapa fasilitas apda sistem komputer yang sebenarnya bukan menjadi haknya, bahkan pihak ini bisa melakukan tindakan erusakan terhadap sitem komputer tersebut. Selain itu pada komputer jaringan pengamanan akses biasanya menjadi tanggung jawab dari administrator sistem. Dalam hal ini seorang administrator sistem harus mampu mengendalikan dan mendokumentasi seluruh akses terhadap sistem komputer dengan baik. Hal ini dimaksudkan untuk mempercepat dan mempermudah pencarian pemasalahan dan solusinya bila suatu saat terjdi masalah dalam sistem komputer tersebut. • Pengamanan Data Pengamanan data dilakukan dengan menerapkan sistem tingkatan atau hierarki akses dimana seseorang hanya dapat mengakses data tertentu saja yang menjadi haknya. Sebagai contoh, departemen pemasaran dari suatu perusahaan hanya dapat mengakses data yang berkaitan dengan pemasaran barang dan tidak dapat mengakses data gaji pegawai, karena data gaji pegawai merupaka wewenang dari departemen personalia. Untuk data yang sifatnya sensitif dapat menggunakan password atau kata sandi. • Pengamanan Komunikasi Jaringan Jaringan disini berkaitan erat dengan pemanfaatan jaringan publik seperti internet. Pengamanan jaringan dapat dilakukan dengan menggunakan kriptografi dimana data yang sifatnya sensitif dapat dienkripsi atau disandikan terlebih dulu sebelum ditransmisikan melalui jaringan. Dengan mentransmisikan data yang telah dienkripsi, maka walaupun data tersebut jatuh ke pihak yang tidak berhak, pihak tersebut tidak dapat mengeti isi dari data tersebut. -Ancaman Keamanan Pada Komputer • Probe Probe atau yang biasa disebut probing adalah usaha untuk mengakses sistem dan mendapatkan informasi tentang sistem • Scan Scan adalah probing dalam jumlah besar menggunakan suatu tool • Account compromise Meliputi User compromize dan root compromize • Packet Snifer Adalah sebuah program yang menangkap data dari paket yang lewat di jaringan. (username,password, dan informasi penting lainnya) • Hacking Hacking adalah tindakan memperoleh akses ke komputer atau jaringan komputer untuk mendapatkan atau mengubah informasi tanpa otorisasi yang sah • Denial-of-Service Serangan Denial-of-service (DoS) mencegah pengguna yang sah dari penggunaan layanan ketika pelaku mendapatkan akses tanpa izin ke mesin atau data. Ini terjadi karena pelaku membanjiri jaringan dengan volume data yang besar atau sengaja menghabiskan sumber daya yang langka atau terbatas, seperti process control blocks atau koneksi jaringan yang tertunda. Atau mereka mengganggu komponen fisik jaringan atau memanipulasi data yang sedang dikirimkan, termasuk data terenkripsi. • Malicious code (Kode Berbahaya) Malicious code adalah program yang menyebabkan kerusakan sistem ketika dijalankan. Virus, worm dan Trojan horse merupakan jenis-jenis malicious code. - Virus komputer adalah sebuah program komputer atau kode program yang merusak sistem komputer dan data dengan mereplikasi dirinya sendiri melalui peng-copy-an ke program lain, boot sector komputer atau dokumen. - Worm adalah virus yang mereplikasi dirinya sendiri yang tidak mengubah file, tetapi ada di memory aktif, menggunakan bagian dari sistem operasi yang otomatis dan biasanya tidak terlihat bagi pengguna. Replikasi mereka yang tidak terkontrol memakan sumber daya sistem, melambatkan atau menghentikan proses lain. Biasanya hanya jika ini terjadi keberadaan worm diketahui. - Trojan horse adalah program yang sepertinya bermanfaat dan/atau tidak berbahaya tetapi sesungguhnya memiliki fungsi merusak seperti unloading hidden program atau command scripts yang membuat sistem rentan gangguan. • Social Engineering / Exploitation of Trust Sekumpulan teknik untuk memanipulasi orang sehingga orang tersebut membocorkan informasi rahasia. Meskipun hal ini mirip dengan permainan kepercayaan atau penipuan sederhana, istilah ini mengacu kepada penipuan untuk mendapatkan informasi atau akses sistem komputer. Beberapa jebakan yang dapat dilakukan diantaranya dengan : - Memanfaatkan kepercayaan orang dalam bersosialisasi dengan komputer. - Memanfaatkan kesalahan orang secara manusiawi misal : kesalahan ketik dll - Bisa dengan cara membuat tampilan Login yang mirip (teknik fake login), • Phishing Tindakan pemalsuan terhadap data atau identitas resmi. -Enkripsi Keamanan Komputer Kategori dari Enkripsi Dalam hal ini terdapat tiga kategori enkripsi, yaitu : Kunci enkripsi rahasia, artinya terdapat sebuah kunci yang digunakan untuk mengenkripsi dan juga sekaligus mendekripsikan informasi. Kunci enkripsi public, artinya dua kunci digunakan satu untuk proses enkripsi dan yang lain untuk proses dekripsi. Fungsi one-way, atau fungsi satu arah adalah suatu fungsi dimana informasi dienkripsi untuk menciptakan “signature” dari informasi asli yang bisa digunakan untuk keperluan autentikasi. Kelebihan dari Enkripsi Kerahasiaan suatu informasi terjamin. Menyediakan autentikasi dan perlindungan integritas pada algoritma checksum/hash. Menanggulangi penyadapan telepon dan email Untuk digital signature Kekurangan dari Enkripsi Penyandian rencana teroris. Penyembunyian record kriminal oleh seorang penjahat. Pesan tidak bisa dibaca bila penerima pesan lupa atau kehilangan kunci. Model – model Enkripsi Symmetric Cryptosystem ( Enkripsi Konvensional) Dalam symmetric cryptosystem,kunci yang digunakan dalam proses enkripsi dan dekripsi adalah sama atau pada prinsipnya identik. Kunci ini pun bisa diturunkan dari kunci lainnya. Oleh karena itu sistem ini sering disebut secret-key ciphersystem. Kunci yang menggunakan teknik enkripsi ini harus betul-betul dirahasiakan. Assymmetric Cryptosystem (Enkripsi public-key) Dalam Assymmetric cryptosystem,kunci yang digunakan terdapat dua buah. Satu kunci yang dapat dipublikasikan deisebut kunci publik (public key), satu lagi kunci yang harus dirahasiakan disebut kunci privat (private key). Secara sedehana proses tersebut diterangkan sebagai berikut : – A mengirimkan pesan kepada B. – A menyandikan pesannya dengan menggunakan kunci publik B. – Bila B ingin membaca pesan
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