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#include <stdio.h>
#include <stdlib.h>
int main(){
char str[256];
char *chare = (char*)malloc(100);
printf("Input: ");
gets(str);
printf("%p\n", str);
} |
gcc -z execstack -o DEP-disabled DEP.c |
Checksec.sh에서 다음과 같은 결과를 출력합니다.
DEP-disabled file: NX disabled
| DEP disabled |
| |
|---|---|---|
| DEP enabled |
|
| DEP enabled |
| |
|---|---|---|
| DEP disabled |
|
# check for NX support
if readelf -W -l $1 2>/dev/null | grep 'GNU_STACK' | grep -q 'RWE'; then
echo -n -e '\033[31mNX disabled\033[m '
else
echo -n -e '\033[32mNX enabled \033[m '
fi |
lazenca0x0@ubuntu:~/Documents/Definition/protection$ readelf -W -l ./DEP-disabled |grep 'GNU_STACK' GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RWE 0x10 lazenca0x0@ubuntu:~/Documents/Definition/protection$ readelf -W -l ./DEP-disabled |grep 'GNU_STACK' | grep 'RWE' GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RWE 0x10 lazenca0x0@ubuntu:~/Documents/Definition/protection$ |
lazenca0x0@ubuntu:~/Documents/Definition/protection$ readelf -W -l ./DEP-enabled |grep 'GNU_STACK' GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RW 0x10 lazenca0x0@ubuntu:~/Documents/Definition/protection$ readelf -W -l ./DEP-enabled |grep 'GNU_STACK' | grep 'RWE' lazenca0x0@ubuntu:~/Documents/Definition/protection$ |
# fallback check for NX support
elif readelf -W -l $1/exe 2>/dev/null | grep 'GNU_STACK' | grep -q 'RWE'; then
echo -n -e '\033[31mNX disabled\033[m '
else
echo -n -e '\033[32mNX enabled \033[m '
fi |
lazenca0x0@ubuntu:~/Documents/Definition/protection$ ps -ef|grep DEP lazenca+ 6586 6369 0 20:22 pts/18 00:00:00 ./DEP-disabled lazenca+ 6607 6173 0 20:23 pts/4 00:00:00 grep --color=auto DEP lazenca0x0@ubuntu:~/Documents/Definition/protection$ readelf -W -l /proc/6586/exe |grep 'GNU_STACK' GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RWE 0x10 lazenca0x0@ubuntu:~/Documents/Definition/protection$ readelf -W -l /proc/6586/exe |grep 'GNU_STACK' | grep 'RWE' GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RWE 0x10 lazenca0x0@ubuntu:~/Documents/Definition/protection$ |
# check cpu nx flag
nxcheck() {
if grep -q nx /proc/cpuinfo; then
echo -n -e '\033[32mYes\033[m\n\n'
else
echo -n -e '\033[31mNo\033[m\n\n'
fi
} |
lazenca0x0@ubuntu:~/Documents/Definition/protection$ grep nx /proc/cpuinfo flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm epb fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt dtherm ida arat pln pts lazenca0x0@ubuntu:~/Documents/Definition/protection$ |