Anil Somayaji

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A method for anomaly detection is introduced in which ``normal'' is defined by short-range correlations in a process' system calls. Initial experiments suggest that the definition is stable during normal behavior for standard UNIX programs. Further, it is able to detect several common intrusions involving sendmail and lpr. This work is part of a research(More)
A method is introducted for detecting intrusions at the level of privileged processes. Evidence is given that short sequences of system calls executed by running processes are a good discriminator between normal and abnormal operating characteristics of several common UNIX programs. Normal behavior is collected in two ways: Synthetically, by exercising as(More)
Diversity is an important source of robustness in biological systems. Computers, by contrast, are notable for their lack of diversity. Although homogeneous systems have many advantages, the beneficial effects of diversity in computing systems have been overlooked, specifically in the area of computer security. Several methods of achieving software diversity(More)
Permission-based security models provide controlled access to various system resources. The expressiveness of the permission set plays an important role in providing the right level of granularity in access control. In this work, we present a methodology for the empirical analysis of permission-based security models which makes novel use of the(More)
This review describes a body of work on computational immune systems that behave analogously to the natural immune system. These artificial immune systems (AIS) simulate the behavior of the natural immune system and in some cases have been used to solve practical engineering problems such as computer security. AIS have several strengths that can complement(More)
Unrestricted information flows are a key security weakness of current web design. Cross-site scripting, cross-site request forgery, and other attacks typically require that information be sent or retrieved from arbitrary, often malicious, web servers. In this paper we propose Same Origin Mutual Approval (SOMA), a new policy for controlling information flows(More)
Self-checking software tamper resistance mechanisms employing checksums, including advanced systems as recently proposed by Chang and Atallah (2002) and Horne et al. (2002) have been promoted as an alternative to other software integrity verification techniques. Appealing aspects include the promise of being able to verify the integrity of software(More)