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GITBOOK-4290: change request with no subject merged in GitBook
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7 changed files with 200 additions and 20 deletions
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@ -702,6 +702,7 @@
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* [EBP2Ret - EBP chaining](reversing-and-exploiting/linux-exploiting-basic-esp/stack-overflow/ebp2ret-ebp-chaining.md)
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* [Ret2win](reversing-and-exploiting/linux-exploiting-basic-esp/stack-overflow/ret2win.md)
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* [Ret2ret](reversing-and-exploiting/linux-exploiting-basic-esp/stack-overflow/ret2ret.md)
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* [Ret2esp / Ret2reg](reversing-and-exploiting/linux-exploiting-basic-esp/stack-overflow/ret2esp-ret2reg.md)
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* [Ret2syscall](reversing-and-exploiting/linux-exploiting-basic-esp/stack-overflow/rop-syscall-execv.md)
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* [Format Strings](reversing-and-exploiting/linux-exploiting-basic-esp/format-strings/README.md)
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* [Format Strings Template](reversing-and-exploiting/linux-exploiting-basic-esp/format-strings/format-strings-template.md)
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@ -715,7 +716,9 @@
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* [Stack Canaries](reversing-and-exploiting/linux-exploiting-basic-esp/common-binary-protections-and-bypasses/stack-canaries/README.md)
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* [BF Forked Stack Canaries](reversing-and-exploiting/linux-exploiting-basic-esp/common-binary-protections-and-bypasses/stack-canaries/bf-forked-stack-canaries.md)
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* [Print Stack Canary](reversing-and-exploiting/linux-exploiting-basic-esp/common-binary-protections-and-bypasses/stack-canaries/print-stack-canary.md)
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* [One Gadget](reversing-and-exploiting/linux-exploiting-basic-esp/one-gadget.md)
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* [Arbitrary Write 2 Exec](reversing-and-exploiting/linux-exploiting-basic-esp/arbitrary-write-2-exec/README.md)
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* [AW2Exec - \_\_malloc\_hook](reversing-and-exploiting/linux-exploiting-basic-esp/arbitrary-write-2-exec/aw2exec-\_\_malloc\_hook.md)
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* [AW2Exec - GOT/PLT](reversing-and-exploiting/linux-exploiting-basic-esp/arbitrary-write-2-exec/aw2exec-got-plt.md)
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* [ELF Basic Information](reversing-and-exploiting/linux-exploiting-basic-esp/elf-tricks.md)
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* [Fusion](exploiting/linux-exploiting-basic-esp/fusion.md)
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@ -162,16 +162,6 @@ De esta forma se obtendría de forma sensilla la dirección donde está la varia
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Esto se puede hacer gracias a que la función execle permite crear un entorno que solo tenga las variables de entorno que se deseen
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**Jump to ESP: Windows Style**
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Debido a que el ESP está apuntando al comienzo del stack siempre, esta técnica consiste con sustituir el EIP con la dirección a una llamada a **jmp esp** o **call esp**. De esta forma, se guarda la shellcode después de la sobreescritura del EIP ya que después de ejecutar el **ret** el ESP se encontrará apuntando a la dirección siguiente, justo donde se ha guardado la shellcode.
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En caso de que no se tenga el ASLR activo en Windows o Linux se puede llamar a **jmp esp** o **call esp** almacenadas en algún objeto compartido. En caso de que esté el ASLR, se podría buscar dentro del propio programa vulnerable.
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Además, el hecho de poder colocar la shellcode después de la corrupción del EIP en vez de en medio del stack, permite que las instrucciones push o pop que se ejecuten en medio de la función no lleguen a tocar la shellcode (cosa que podría ocurrir en caso de ponerse en medio del stack de la función).
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De forma muy similar a esto si sabemos que una función devuelve la dirección donde está guardada la shellcode se puede llamar a **call eax** o **jmp eax (ret2eax).**
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**Integer overflows**
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Este tipo de overflows se producen cuando una variable no está preparada para soportar un número tan grande como se le pasa, posiblemente por una confusión entre variables con y sin signo, por ejemplo:
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@ -0,0 +1,45 @@
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# AW2Exec - \_\_malloc\_hook
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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Other ways to support HackTricks:
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* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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## **Malloc Hook**
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As you can [Official GNU site](https://www.gnu.org/software/libc/manual/html\_node/Hooks-for-Malloc.html), the variable **`__malloc_hook`** is a pointer pointing to the **address of a function that will be called** whenever `malloc()` is called **stored in the data section of the libc library**. Therefore, if this address is overwritten with a **One Gadget** for example and `malloc` is called, the **One Gadget will be called**.
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To call malloc it's possible to wait for the program to call it or by **calling `printf("%10000$c")`** which allocates too bytes many making `libc` calling malloc to allocate them in the heap.
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More info about One Gadget in:
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{% content-ref url="../one-gadget.md" %}
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[one-gadget.md](../one-gadget.md)
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{% endcontent-ref %}
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## References
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* [https://ir0nstone.gitbook.io/notes/types/stack/one-gadgets-and-malloc-hook](https://ir0nstone.gitbook.io/notes/types/stack/one-gadgets-and-malloc-hook)
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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Other ways to support HackTricks:
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* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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@ -54,6 +54,12 @@ If **`system`** **isn't used** by the script, the system function **won't** have
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You can see the PLT addresses with **`objdump -j .plt -d ./vuln_binary`**
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## **One Gadget**
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{% content-ref url="../one-gadget.md" %}
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[one-gadget.md](../one-gadget.md)
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{% endcontent-ref %}
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## **Protections**
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The **FullRELRO** protection is meant to protect agains this kind of technique by resolving all the addresses of the functions when the binary is started and making the **GOT table read only** after it:
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@ -62,6 +68,11 @@ The **FullRELRO** protection is meant to protect agains this kind of technique b
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[relro.md](../common-binary-protections-and-bypasses/relro.md)
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{% endcontent-ref %}
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## References
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* [https://ir0nstone.gitbook.io/notes/types/stack/got-overwrite/exploiting-a-got-overwrite](https://ir0nstone.gitbook.io/notes/types/stack/got-overwrite/exploiting-a-got-overwrite)
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* [https://ir0nstone.gitbook.io/notes/types/stack/one-gadgets-and-malloc-hook](https://ir0nstone.gitbook.io/notes/types/stack/one-gadgets-and-malloc-hook)
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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@ -0,0 +1,47 @@
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# One Gadget
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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Other ways to support HackTricks:
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* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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## Basic Information
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[**One Gadget**](https://github.com/david942j/one\_gadget) allows to obtain a shell instead of using **system** and **"/bin/sh". One Gadget** will find inside the libc library some way to obtain a shell (`execve("/bin/sh")`) using just one **address**.\
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However, normally there are some constrains, the most common ones and easy to avoid are like `[rsp+0x30] == NULL` As you control the values inside the **RSP** you just have to send some more NULL values so the constrain is avoided.
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.png>)
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```python
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ONE_GADGET = libc.address + 0x4526a
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rop2 = base + p64(ONE_GADGET) + "\x00"*100
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```
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To the address indicated by One Gadget you need to **add the base address where `libc`** is loaded.
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{% hint style="success" %}
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One Gadget is a **great help for Arbitrary Write 2 Exec techniques** and might **simplifies ROP** chains as you only need to call one address (and fulfill the requirements).
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{% endhint %}
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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Other ways to support HackTricks:
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* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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@ -0,0 +1,90 @@
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# Ret2esp / Ret2reg
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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Other ways to support HackTricks:
|
||||
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* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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## **Rest2esp**
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**Because the ESP (Stack Pointer) always points to the top of the stack**, this technique involves replacing the EIP (Instruction Pointer) with the address of a **`jmp esp`** or **`call esp`** instruction. By doing this, the shellcode is placed right after the overwritten EIP. When the `ret` instruction executes, ESP points to the next address, precisely where the shellcode is stored.
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If **Address Space Layout Randomization (ASLR)** is not enabled in Windows or Linux, it's possible to use `jmp esp` or `call esp` instructions found in shared libraries. However, with [**ASLR**](../common-binary-protections-and-bypasses/aslr/) active, one might need to look within the vulnerable program itself for these instructions (and you might need to defeat [**PIE**](../common-binary-protections-and-bypasses/pie/)).
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Moreover, being able to place the shellcode **after the EIP corruption**, rather than in the middle of the stack, ensures that any `push` or `pop` instructions executed during the function's operation don't interfere with the shellcode. This interference could happen if the shellcode were placed in the middle of the function's stack.
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### Lacking space
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If you are lacking space to write after overwriting RIP (maybe just a few bytes), write an initial `jmp` shellcode like:
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```armasm
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sub rsp, 0x30
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jmp rsp
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```
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And write the shellcode early in the stack.
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### Example
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You can find an example of this technique in [https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode/using-rsp](https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode/using-rsp) with a final exploit like:
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```python
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from pwn import *
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elf = context.binary = ELF('./vuln')
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p = process()
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jmp_rsp = next(elf.search(asm('jmp rsp')))
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payload = b'A' * 120
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payload += p64(jmp_rsp)
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payload += asm('''
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sub rsp, 10;
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jmp rsp;
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''')
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pause()
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p.sendlineafter('RSP!\n', payload)
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p.interactive()
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```
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## Ret2reg
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Similarly, if we know a function returns the address where the shellcode is stored, we can leverage **`call eax`** or **`jmp eax`** instructions (known as **ret2eax** technique), offering another method to execute our shellcode. Just like eax, **any other register** containing an interesting address could be used (**ret2reg**).
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### Example
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You can find an example here: [https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode/ret2reg/using-ret2reg](https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode/ret2reg/using-ret2reg)
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## Protections
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* [**NX**](../common-binary-protections-and-bypasses/no-exec-nx.md): If the stack isn't executable this won't help as we need to place the shellcode in the stack and jump to execute it.
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* [**ASLR**](../common-binary-protections-and-bypasses/aslr/) & [**PIE**](../common-binary-protections-and-bypasses/pie/): Those can make harder to find a instruction to jump to esp or any other register.
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## References
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* [https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode](https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode)
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* [https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode/using-rsp](https://ir0nstone.gitbook.io/notes/types/stack/reliable-shellcode/using-rsp)
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
|
||||
|
||||
Other ways to support HackTricks:
|
||||
|
||||
* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
||||
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
||||
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
||||
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
|
||||
* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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@ -97,17 +97,11 @@ for off in range(0xb7000000, 0xb8000000, 0x1000):
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* If attacking a remote server, you could try to **burte-force the address of the `libc` function `usleep`**, passing as argument 10 (for example). If at some point the **server takes 10s extra to respond**, you found the address of this function.
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## ONE\_GADGET
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## One Gadget
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[**ONE\_GADGET** ](https://github.com/david942j/one\_gadget)allows to obtain a shell instead of using **system** and **"/bin/sh". ONE\_GADGET** will find inside the libc library some way to obtain a shell using just one **ROP address**.\
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However, normally there are some constrains, the most common ones and easy to avoid are like `[rsp+0x30] == NULL` As you control the values inside the **RSP** you just have to send some more NULL values so the constrain is avoided.
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.png>)
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```python
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ONE_GADGET = libc.address + 0x4526a
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rop2 = base + p64(ONE_GADGET) + "\x00"*100
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```
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{% content-ref url="../../one-gadget.md" %}
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[one-gadget.md](../../one-gadget.md)
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{% endcontent-ref %}
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## x86 Ret2lib Code Example
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