jeffrin – Page 28

sample session with “ss” command to show details on network

$ss -t State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 0 0 192.168.0.100:57982 216.58.197.34:https ESTAB 0 0 192.168.0.100:56572 216.58.196.98:https ESTAB 0 0 192.168.0.100:51440 216.58.220.34:https ESTAB 0 0 192.168.0.100:56850 216.58.196.110:https ESTAB 0 0 192.168.0.100:42946 216.58.220.46:https ESTAB 0 0 192.168.0.100:42758 216.58.197.46:https ESTAB 0 0 192.168.0.100:32912 216.58.220.33:https ESTAB 0 0 192.168.0.100:40452 216.58.220.38:https ESTAB 0 0 192.168.0.100:51128 182.79.251.80:https ESTAB …

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Capturing TCP Flags with tcpdump. Capture ACK or SYN packets

ABOUT TCP FLAGS They are control bits that indicate different connection states or information about how a packet should be handled. FLAGS CWR – Congestion Window Reduced (CWR) flag is set by the sending host to indicate that it received a TCP segment with the ECE flag set (added to header by RFC 3168). ECE …

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Hacking with ANSI C signal Handling

$sudo strace -e trace=signal -p 1 [sudo] password for jeffrin: Process 1 attached kill(4659, SIGTERM) = 0 kill(4659, SIGCONT) = 0 $gcc crtlc1-p1.c $./a.out Hello world Hello world Hello world Hello world Hello world Hello world Hello world Hello world Hello world ^Ci got a signal 2 Hello world Hello world ^C $cat crtlc1-p1.c #include …

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Collecting information from sysfs about cpu events

$sudo cat /sys/devices/cpu/events/cache-misses event=0x81 $sudo cat /sys/devices/cpu/type 4 $sudo cat /sys/devices/cpu/events/branch-instructions event=0xc2 $sudo cat /sys/devices/cpu/events/branch-instructions event=0xc2 $sudo cat /sys/devices/cpu/events/branch-instructions event=0xc2 $sudo cat /sys/devices/cpu/events/branch-instructions event=0xc2 $sudo cat /sys/devices/cpu/events/branch-misses event=0xc3 $sudo cat /sys/devices/cpu/events/branch-misses event=0xc3 $sudo cat /sys/devices/cpu/events/cache-references event=0x80 $sudo cat /sys/devices/cpu/events/cpu-cycles event=0x76 $sudo cat /sys/devices/cpu/events/instructions event=0xc0 $

Example related — Recovering typical deleted file in GNU/Linux

$which glxgears /usr/bin/glxgears $rm /usr/bin/glxgears rm: remove write-protected regular file ‘/usr/bin/glxgears’? y rm: cannot remove ‘/usr/bin/glxgears’: Permission denied $sudo rm /usr/bin/glxgears [sudo] password for jeffrin: $ps aux | grep glxgears jeffrin 2469 4.4 0.6 157656 20888 pts/0 Sl+ 22:43 0:07 glxgears jeffrin 2515 0.0 0.0 12656 1560 pts/1 S+ 22:46 0:00 grep glxgears $sudo cat …

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Example for – Trace all system calls which involve process management

$strace -e trace=process python dig.py execve(“/usr/bin/python”, [“python”, “dig.py”], [/* 39 vars */]) = 0 arch_prctl(ARCH_SET_FS, 0x7feb563b4700) = 0 I think lscpu command is using proc filesystem to get data. /* /sys paths */ #define _PATH_SYS_SYSTEM “/sys/devices/system” #define _PATH_SYS_CPU _PATH_SYS_SYSTEM “/cpu” #define _PATH_SYS_NODE _PATH_SYS_SYSTEM “/node” #define _PATH_PROC_XEN “/proc/xen” #define _PATH_PROC_XENCAP _PATH_PROC_XEN “/capabilities” #define _PATH_PROC_CPUINFO “/proc/cpuinfo” #define …

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Hacking with a JavaScript Program

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Hacking with strace to find about write calls in a program

$strace -e write python dig.py write(1, “\33[31mI think lscpu command is us”…, 69I think lscpu command is using proc filesystem to get data. ) = 69 write(1, “\33[31m/* /sys paths */\33[0m\n”, 26/* /sys paths */ ) = 26 write(1, “\33[31m#define _PATH_SYS_SYSTEM “…, 63#define _PATH_SYS_SYSTEM “/sys/devices/system” ) = 63 write(1, “\33[31m#define _PATH_SYS_CPU “…, 65#define _PATH_SYS_CPU _PATH_SYS_SYSTEM …

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Internal of lscpu command

I think lscpu command is using proc filesystem to get data. /* /sys paths */ #define _PATH_SYS_SYSTEM “/sys/devices/system” #define _PATH_SYS_CPU _PATH_SYS_SYSTEM “/cpu” #define _PATH_SYS_NODE _PATH_SYS_SYSTEM “/node” #define _PATH_PROC_XEN “/proc/xen” #define _PATH_PROC_XENCAP _PATH_PROC_XEN “/capabilities” #define _PATH_PROC_CPUINFO “/proc/cpuinfo” #define _PATH_PROC_PCIDEVS “/proc/bus/pci/devices” #define _PATH_PROC_SYSINFO “/proc/sysinfo” #define _PATH_PROC_STATUS “/proc/self/status” #define _PATH_PROC_VZ “/proc/vz” #define _PATH_PROC_BC “/proc/bc” #define _PATH_PROC_DEVICETREE “/proc/device-tree” #define …

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Looking into a few commands with python interactive shell

ABOUT PYTHON Python is an interpreted, high-level, general-purpose programming language. Created by Guido van Rossum and first released in 1991, Python has a design philosophy that emphasizes code readability, notably using significant whitespace. It provides constructs that enable clear programming on both small and large scales.[26] Van Rossum led the language community until stepping down …

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