The system must implement non-executable program stacks.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-11999	GEN003540	SV-27414r1_rule	ECSC-1	Medium

Description
A common type of exploit is the stack buffer overflow. An application receives, from an attacker, more data than it is prepared for and stores this information on its stack, writing beyond the space reserved for it. This can be designed to cause execution of the data written on the stack. One mechanism to mitigate this vulnerability is for the system to not allow the execution of instructions in sections of memory identified as part of the stack.

Description

A common type of exploit is the stack buffer overflow. An application receives, from an attacker, more data than it is prepared for and stores this information on its stack, writing beyond the space reserved for it. This can be designed to cause execution of the data written on the stack. One mechanism to mitigate this vulnerability is for the system to not allow the execution of instructions in sections of memory identified as part of the stack.

STIG	Date
Red Hat Enterprise Linux 5 Security Technical Implementation Guide	2016-06-01

Details

Check Text ( C-28600r1_chk )
Verify "exec_shield" and "randomize_va_space" have not been changed from the default "1" settings. Procedure: #sysctl kernel.exec-shield If the return value is not: kernel.exec-shield = 1 this is a finding. #sysctl kernel.randomize_va_space If the return value is not: kernel.randomize_va_space = 1 this is a finding.

Fix Text (F-24686r1_fix)
Examine /etc/sysctl.conf for "kernel.exec-shield" and "kernel.randomize_va_space" entries and if found remove them. The system default of "1" enables these modules.