Computer security | |
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[Site] James Madison University - Computer Security Computer security imposes requirements on computers that are different from most system requirements because they often take the form of constraints on what computers are not supposed to do. This makes computer security particularly challenging because we find it hard enough just to make computer programs do everything they are designed to do correctly. Furthermore, negative requirements are deceptively complicated to satisfy and require exhaustive testing to verify, which is impractical for most computer programs. Computer security provides a technical strategy to convert negative requirements to positive enforceable rules. For this reason, computer security is often more technical and mathematical than some computer science fields. [News] Treasury Office Faults IRS Computer Security Typical approaches to improving computer security (in approximate order of strength) can include the following: [Image]
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Secure operating systemsOne use of the term computer security refers to technology to implement a secure operating system. Much of this technology is based on science developed in the 1980s and used to produce what may be some of the most impenetrable operating systems ever. Though still valid, the technology is in limited use today, primarily because it imposes some changes to system management and also because it is not widely understood. Such ultra-strong secure operating systems are based on operating system kernel technology that can guarantee that certain security policies are absolutely enforced in an operating environment. An example of such a Computer security policy is the Bell-LaPadula model. The strategy is based on a coupling of special microprocessor hardware features, often involving the memory management unit, to a special correctly implemented operating system kernel. This forms the foundation for a secure operating system which, if certain critical parts are designed and implemented correctly, can ensure the absolute impossibility of penetration by hostile elements. This capability is enabled because the configuration not only imposes a security policy, but in theory completely protects itself from corruption. Ordinary operating systems, on the other hand, lack the features that assure this maximal level of security. The design methodology to produce such secure systems is precise, deterministic and logical.[Auction] Notebook Laptop Computer Security Chain Lock w/# Systems designed with such methodology represent the state of the art of computer security although products using such security are not widely known. In sharp contrast to most kinds of software, they meet specifications with verifiable certainty comparable to specifications for size, weight and power. Secure operating systems designed this way are used primarily to protect national security information, military secrets, and the data of international financial institutions. These are very powerful security tools and very few secure operating systems have been certified at the highest level (Orange Book A-1) to operate over the range of "Top Secret" to "unclassified" (including Honeywell SCOMP, USAF SACDIN, NSA Blacker and Boeing MLS LAN.) The assurance of security depends not only on the soundness of the design strategy, but also on the assurance of correctness of the implementation, and therefore there are degrees of security strength defined for COMPUSEC. The Common Criteria quantifies security strength of products in terms of two components, security functionality and assurance level (such as EAL levels), and these are specified in a Protection Profile for requirements and a Security Target for product descriptions. None of these ultra-high assurance secure general purpose operating systems have been produced for decades or certified under the Common Criteria. [Post] Information Security Analyst at Joliet Junior College Secure operating systems designed to meet medium robustness levels of security functionality and assurance have seen wider use within both government and commercial markets. Medium robust systems typically provide nearly all of the security features of the most advanced secure operating systems but do so at a lower assurance level (such as EAL4 or EAL5). These systems are found in use on web servers, guards, database servers, and management hosts and are used not only to protect the data stored on these systems but also to provide a high level of protection for network connections and routing services. [Book] Computer Security: Art and Science Addison-Wesley Professional
Security architectureSecurity Architecture can be defined as the design artifacts that describe how the security controls (security countermeasures) are positioned, and how they relate to the overall information technology architecture. These controls serve the purpose to maintain the system’s quality attributes, among them confidentiality, integrity, availability, accountability and assurance." Definitions: IT Security Architecture. SecurityArchitecture.org, Jan, 2008. In simpler words, a security architecture is the plan that shows where security measures need to be placed. If the plan describes a specific solution then, prior to building such a plan, one would make a risk analysis. If the plan describes a generic high level design then (reference architecture) then the plan should be based on a threat analysis.[Site] Home Computer Security
Security by designThe technologies of computer security are based on logic. There is no universal standard notion of what secure behavior is. "Security" is a concept that is unique to each situation. Security is extraneous to the function of a computer application, rather than ancillary to it, thus security necessarily imposes restrictions on the application's behavior.[News] Treasury office faults IRS computer security There are several approaches to security in computing, sometimes a combination of approaches is valid:
[Image] Many systems have unintentionally resulted in the first possibility. Since approach two is expensive and non-deterministic, its use is very limited. Approaches one and three lead to failure. Because approach number four is often based on hardware mechanisms and avoids abstractions and a multiplicity of degrees of freedom, it is more practical. Combinations of approaches two and four are often used in a layered architecture with thin layers of two and thick layers of four. [Video] DaySafe 200: Anti-theft backpack by PacSafe There are myriad strategies and techniques used to design security systems. There are few, if any, effective strategies to enhance security after design. [Auction] NOTEBOOK LAPTOP COMPUTER LOCK SECURITY CABLE CHAIN One technique enforces the principle of least privilege to great extent, where an entity has only the privileges that are needed for its function. That way even if an attacker gains access to one part of the system, fine-grained security ensures that it is just as difficult for them to access the rest. [Post] Computer Security Professional Furthermore, by breaking the system up into smaller components, the complexity of individual components is reduced, opening up the possibility of using techniques such as automated theorem proving to prove the correctness of crucial software subsystems. This enables a closed form solution to security that works well when only a single well-characterized property can be isolated as critical, and that property is also assessable to math. Not surprisingly, it is impractical for generalized correctness, which probably cannot even be defined, much less proven. Where formal correctness proofs are not possible, rigorous use of code review and unit testing represent a best-effort approach to make modules secure. [Book] Computer Security: Principles and Practice Prentice Hall The design should use "defense in depth", where more than one subsystem needs to be violated to compromise the integrity of the system and the information it holds. Defense in depth works when the breaching of one security measure does not provide a platform to facilitate subverting another. Also, the cascading principle acknowledges that several low hurdles does not make a high hurdle. So cascading several weak mechanisms does not provide the safety of a single stronger mechanism. [Site] Symantec - Antivirus & Security Software Subsystems should default to secure settings, and wherever possible should be designed to "fail secure" rather than "fail insecure" (see fail safe for the equivalent in safety engineering). Ideally, a secure system should require a deliberate, conscious, knowledgeable and free decision on the part of legitimate authorities in order to make it insecure. [News] Treasury office faults IRS computer security In addition, security should not be an all or nothing issue. The designers and operators of systems should assume that security breaches are inevitable.Full audit trails should be kept of system activity, so that when a security breach occurs, the mechanism and extent of the breach can be determined. Storing audit trails remotely, where they can only be appended to, can keep intruders from covering their tracks. Finally, full disclosure helps to ensure that when bugs are found the "window of vulnerability" is kept as short as possible. [Image]
Early history of security by designThe early Multics operating system was notable for its early emphasis on computer security by design, and Multics was possibly the very first operating system to be designed as a secure system from the ground up. In spite of this, Multics' security was broken, not once, but repeatedly. The strategy was known as 'penetrate and test' and has become widely known as a non-terminating process that fails to produce computer security. This led to further work on computer security that prefigured modern security engineering techniques producing closed form processes that terminate.[Video] Scan Remove Spyware And Adware
Secure codingIf the operating environment is not based on a secure operating system capable of maintaining a domain for its own execution, and capable of protecting application code from malicious subversion, and capable of protecting the system from subverted code, then high degrees of security are understandably not possible. While such secure operating systems are possible and have been implemented, most commercial systems fall in a 'low security' category because they rely on features not supported by secure operating systems (like portability, et al.). In low security operating environments, applications must be relied on to participate in their own protection. There are 'best effort' secure coding practices that can be followed to make an application more resistant to malicious subversion.[Auction] NEW COMPUTER NOTEBOOK LAPTOP LOCK SECURITY CABLE CHAIN In commercial environments, the majority of software subversion vulnerabilities result from a few known kinds of coding defects. Common software defects include buffer overflows, format string vulnerabilities, integer overflow, and code/command injection. [Post] Pepsky All - in - One v4.5.0.1000 Some common languages such as C and C++ are vulnerable to all of these defects (see Seacord, "Secure Coding in C and C++"). Other languages, such as Java, are more resistant to some of these defects, but are still prone to code/command injection and other software defects which facilitate subversion. [Book] Introduction to Computer Security Addison-Wesley Professional Recently another bad coding practice has come under scrutiny; dangling pointers. The first known exploit for this particular problem was presented in July 2007. Before this publication the problem was known but considered to be academic and not practically exploitable. New hacking technique exploits common programming error. SearchSecurity.com, July 2007 [Site] Computer Security Day In summary, 'secure coding' can provide significant payback in low security operating environments, and therefore worth the effort. Still there is no known way to provide a reliable degree of subversion resistance with any degree or combination of 'secure coding.' [News] Treasury office faults IRS computer security
Capabilities vs. ACLsWithin computer systems, the two fundamental means of enforcing privilege separation are access control lists (ACLs) and capabilities. The semantics of ACLs have been proven to be insecure in many situations (e.g., Confused deputy problem). It has also been shown that ACL's promise of giving access to an object to only one person can never be guaranteed in practice. Both of these problems are resolved by capabilities. This does not mean practical flaws exist in all ACL-based systems, but only that the designers of certain utilities must take responsibility to ensure that they do not introduce flaws.[Image] Unfortunately, for various historical reasons, capabilities have been mostly restricted to research operating systems and commercial OSs still use ACLs. Capabilities can, however, also be implemented at the language level, leading to a style of programming that is essentially a refinement of standard object-oriented design. An open source project in the area is the E language. [Video] How I Removed Spyware from Computer Easily First the Plessey System 250 and then Cambridge CAP computer demonstrated the use of capabilities, both in hardware and software, in the 1970s, so this technology is hardly new. A reason for the lack of adoption of capabilities may be that ACLs appeared to offer a 'quick fix' for security without pervasive redesign of the operating system and hardware. [Auction] NOTEBOOK COMPUTER LOCK SECURITY CABLE CHAIN w/# The most secure computers are those not connected to the Internet and shielded from any interference. In the real world, the most security comes from operating systems where security is not an add-on, such as OS/400 from IBM. This almost never shows up in lists of vulnerabilities for good reason. Years may elapse between one problem needing remediation and the next. [Post] Wise Registry Cleaner Pro v3.73.131 A good example of a secure system is EROS. But see also the article on secure operating systems. TrustedBSD is an example of an open source project with a goal, among other things, of building capability functionality into the FreeBSD operating system. Much of the work is already done. [Book] Principles of Computer Security: Security+ and Beyond The McGraw-Hill Companies, Inc.
ApplicationsComputer security is critical in almost any technology-driven industry which operates on computer systems. The issues of computer based systems and addressing their countless vulnerabilities are an integral part of maintaining an operational industry. J. C. Willemssen, "FAA Computer Security". GAO/T-AIMD-00-330. Presented at Committee on Science, House of Representatives, 2000.[Site] National Institute of Standards and Technology: Computer Security ...
In aviationThe aviation industry is especially important when analyzing computer security because the involved risks include expensive equipment and cargo, transportation infrastructure and even human life. Security can be compromised by hardware and software malpractice, human error and faulty operating environments. Threats which exploit computer vulnerabilities can stem from sabotage, espionage, industrial competition, terrorist attack, mechanical malfunction and human error. P. G. Neumann, "Computer Security in Aviation," presented at International Conference on Aviation Safety and Security in the 21st Century, White House Commission on Safety and Security, 1997.[News] Treasury office faults IRS computer security The consequences of a successful intentional or accidental misuse of a computer system in the aviation industry range from loss of confidentiality to loss of system integrity, which may lead to more serious concerns, like data theft or loss, network and air traffic control outages, which can lead to airport closures, loss of aircraft or even death of passengers. Military systems which control munitions pose an even greater risk, one which is evident enough not to warrant a further explanation. [Image] A proper attack does not need to be very high tech, or well funded, for a power outage at an airport alone can cause repercussions worldwide. J. Zellan, Aviation Security. Hauppauge, NY: Nova Science, 2003, pp. 65-70.. One of the easiest and, arguably, the most difficult to trace security vulnerabilities is achievable by transmitting unauthorized communications over specific radio frequencies. These transmissions may spoof air traffic controllers or simply disrupt communications altogether. These incidents are very common, having altered flight courses of commercial aircraft and caused panic and confusion in the past. Controlling aircraft over oceans is especially dangerous because radar surveillance only extends 175 to 225 miles offshore. Beyond the radars' sight, controllers must rely on periodic radio communications through a third party. [Video] WINDOWS XP Tricks 2 Lightning, power fluctuations, surges, brown-outs, blown fuses, and various other power outages instantly disable all computer systems, since they are dependent on electrical source. Other accidental and intentional faults have caused significant disruption of safety critical systems throughout the last few decades and dependence on reliable communication and electrical power onlyjeopardizes computer safety. [Auction] NOTEBOOK COMPUTER LOCK SECURITY CABLE CHAIN w/#
Notable system accidentsIn 1983, Korean Airlines Flight 007, a Boeing 747 was shot down by Soviet SU-15 jets after a navigation computer malfunction caused the aircraft to steer 185 miles off course into Soviet Union airspace. All 269 passengers were killed. KAL Flight 007. Check-six.com, Mar 2008[Post] Privacy Shield v3.0.81 In 1994, over a hundred intrusions were made by unidentified hackers into the Rome Laboratory, the US Air Force’s main command and research facility. Using trojan horse viruses, hackers were able to obtain unrestricted access to Rome’s networking systems and remove traces of their activities. The intruders were able to obtain classified files, such as air tasking order systems data and furthermore able to penetrate connected networks of National Aeronautics and Space Administration's Goddard Space Flight Center, Wright-Patterson Air Force Base, some Defense contractors, and other private sector organizations, by posing asa trusted Rome center user. Information Security. United States Department of Defense, 1986 [Book] Computer Security Wiley Electromagnetic interference is another threat to computer safety and in 1989, a United States Air Force F-16 jet accidentally dropped a 230 kg bomb in West Georgia after unspecified interference caused the jet’s computers to release it. Air Force Bombs Georgia. The Risks Digest, vol. 8, no. 72, May 1989 [Site] Computer Security Products, Inc A similar telecommunications accident also happened in 1994, when two UH-60 Blackhawk helicopters were destroyed by F-15 aircraft in Iraq because the IFF system’s encryption system malfunctioned. [News] Treasury office faults IRS computer security
TerminologyThe following terms used in engineering secure systems are explained below.
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[Video] What is Spyware A bigger OS, capable of providing a standard API like POSIX, can be built on a secure microkernel using small API servers running as normal programs. If one of these API servers has a bug, the kernel and the other servers are not affected: e.g. Hurd or Minix 3. [Auction] NOTEBOOK LAPTOP COMPUTER LOCK SECURITY CABLE CHAIN
[Post] Automatic Feature Selection for Anomaly Detection. Secure cryptoprocessors can be used to leverage physical security techniques into protecting the security of the computer system. [Book] Computer Security Lab Manual (Information Assurance & Security) Career Education
[Site] History of Computer Security Some of the following items may belong to the computer insecurity article: [News] Burning Question: How Much Computer Security Is Enough?
[Image] techniques involve transforming information, scrambling it so it becomes unreadable during transmission. The intended recipient can unscramble the message, but eavesdroppers cannot.]] [Video] Totally Free Spyware Removal Do you Even Have Spyware
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[Site] computer security: Definition from Answers.com
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References
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Further reading
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