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Title: Detecting Secure Memory Deallocation Violations with CBMC
Scrubbing sensitive data before releasing memory is a widely accepted but often ignored programming practice for developing secure software. Consequently, confidential data such as cryptographic keys, passwords, and personal data, can remain in memory indefinitely, thereby increasing the risk of exposure to hackers who can retrieve the data using memory dumps or exploit vulnerabilities such as Heartbleed and Etherleak. We propose an approach for detecting a specific memory safety bug called Improper Clearing of Heap Memory Before Release, also known as Common Weakness Enumeration 244, in C programs. The CWE-244 bug in a program allows the leakage of confidential information when a variable is not wiped before heap memory is freed. Our approach combines taint analysis and model checking to detect this weakness. We have three main phases: (1) perform a coarse flow-insensitive inter-procedural static analysis on the program to construct a set of pointer variables that could point to sensitive data; (2) instrument the program with required dynamic variable tracking, and assertion logic for memory wiping before deallocation; and (3) invoke a model checker, the C-Bounded Model Checker (CBMC) in our case, to detect assertion violation in the instrumented program. We develop a tool, \toolname, implementing our instrumentation based more » algorithm, and we provide experimental validation on the Juliet Test Suite --- the tool is able to detect all the CWE-244 instances present in the test suite. To the best of our knowledge, this is the first work which presents a solution to the problem of detecting unscrubbed secure memory deallocation violations in programs. « less
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Award ID(s):
Publication Date:
Journal Name:
CPSS '22: Proceedings of the 8th ACM on Cyber-Physical System Security Workshop
Page Range or eLocation-ID:
27 to 38
Sponsoring Org:
National Science Foundation
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