base on A repository for learning various heap exploitation techniques. # Educational Heap Exploitation This repo is for learning various heap exploitation techniques. We use Ubuntu's Libc releases as the gold-standard. Each technique is verified to work on corresponding Ubuntu releases. You can run `apt source libc6` to download the source code of the Libc your are using on Debian-based operating system. You can also click :arrow_forward: to debug the technique in your browser using gdb. We came up with the idea during a hack meeting, and have implemented the following techniques: | File | :arrow_forward: | Technique | Glibc-Version | Patch | Applicable CTF Challenges | |------|-----|-----------|---------------|-------|---------------------------| | [first_fit.c](first_fit.c) | | Demonstrating glibc malloc's first-fit behavior. | | | | | [calc_tcache_idx.c](calc_tcache_idx.c)| | Demonstrating glibc's tcache index calculation.| | | | | [fastbin_dup.c](glibc_2.35/fastbin_dup.c) | <a href="https://wargames.ret2.systems/level/how2heap_fastbin_dup_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Tricking malloc into returning an already-allocated heap pointer by abusing the fastbin freelist. | latest | | | | [fastbin_dup_into_stack.c](glibc_2.35/fastbin_dup_into_stack.c) | <a href="https://wargames.ret2.systems/level/how2heap_fastbin_dup_into_stack_2.23" title="Debug Technique In Browser">:arrow_forward:</a> | Tricking malloc into returning a nearly-arbitrary pointer by abusing the fastbin freelist. | latest | | [9447-search-engine](https://github.com/ctfs/write-ups-2015/tree/master/9447-ctf-2015/exploitation/search-engine), [0ctf 2017-babyheap](http://uaf.io/exploitation/2017/03/19/0ctf-Quals-2017-BabyHeap2017.html) | | [fastbin_dup_consolidate.c](glibc_2.35/fastbin_dup_consolidate.c) | <a href="https://wargames.ret2.systems/level/how2heap_fastbin_dup_consolidate_2.23" title="Debug Technique In Browser">:arrow_forward:</a> | Tricking malloc into returning an already-allocated heap pointer by putting a pointer on both fastbin freelist and the top chunk. | latest | | [Hitcon 2016 SleepyHolder](https://github.com/mehQQ/public_writeup/tree/master/hitcon2016/SleepyHolder) | | [unsafe_unlink.c](glibc_2.35/unsafe_unlink.c) | <a href="https://wargames.ret2.systems/level/how2heap_unsafe_unlink_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting free on a corrupted chunk to get arbitrary write. | latest | | [HITCON CTF 2014-stkof](http://acez.re/ctf-writeup-hitcon-ctf-2014-stkof-or-modern-heap-overflow/), [Insomni'hack 2017-Wheel of Robots](https://gist.github.com/niklasb/074428333b817d2ecb63f7926074427a) | | [house_of_spirit.c](glibc_2.35/house_of_spirit.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_spirit_2.23" title="Debug Technique In Browser">:arrow_forward:</a> | Frees a fake fastbin chunk to get malloc to return a nearly-arbitrary pointer. | latest | | [hack.lu CTF 2014-OREO](https://github.com/ctfs/write-ups-2014/tree/master/hack-lu-ctf-2014/oreo) | | [poison_null_byte.c](glibc_2.35/poison_null_byte.c) | <a href="https://wargames.ret2.systems/level/how2heap_poison_null_byte_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting a single null byte overflow. | latest | | [PlaidCTF 2015-plaiddb](https://github.com/ctfs/write-ups-2015/tree/master/plaidctf-2015/pwnable/plaiddb), [BalsnCTF 2019-PlainNote](https://gist.github.com/st424204/6b5c007cfa2b62ed3fd2ef30f6533e94?fbclid=IwAR3n0h1WeL21MY6cQ_C51wbXimdts53G3FklVIHw2iQSgtgGo0kR3Lt-1Ek)| | [house_of_lore.c](glibc_2.35/house_of_lore.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_lore_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Tricking malloc into returning a nearly-arbitrary pointer by abusing the smallbin freelist. | latest | | | | [overlapping_chunks.c](glibc_2.27/overlapping_chunks.c) | <a href="https://wargames.ret2.systems/level/how2heap_overlapping_chunks_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploit the overwrite of a freed chunk size in the unsorted bin in order to make a new allocation overlap with an existing chunk | < 2.29 | [patch](https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b90ddd08f6dd688e651df9ee89ca3a69ff88cd0c) | [hack.lu CTF 2015-bookstore](https://github.com/ctfs/write-ups-2015/tree/master/hack-lu-ctf-2015/exploiting/bookstore), [Nuit du Hack 2016-night-deamonic-heap](https://github.com/ctfs/write-ups-2016/tree/master/nuitduhack-quals-2016/exploit-me/night-deamonic-heap-400) | | [overlapping_chunks_2.c](glibc_2.23/overlapping_chunks_2.c) | <a href="https://wargames.ret2.systems/level/how2heap_overlapping_chunks_2_2.23" title="Debug Technique In Browser">:arrow_forward:</a> | Exploit the overwrite of an in use chunk size in order to make a new allocation overlap with an existing chunk | < 2.29|[patch](https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b90ddd08f6dd688e651df9ee89ca3a69ff88cd0c) | | | [mmap_overlapping_chunks.c](glibc_2.35/mmap_overlapping_chunks.c) | | Exploit an in use mmap chunk in order to make a new allocation overlap with a current mmap chunk | latest | | | | [house_of_force.c](glibc_2.27/house_of_force.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_force_2.27" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting the Top Chunk (Wilderness) header in order to get malloc to return a nearly-arbitrary pointer | < 2.29 | [patch](https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=30a17d8c95fbfb15c52d1115803b63aaa73a285c) | [Boston Key Party 2016-cookbook](https://github.com/ctfs/write-ups-2016/tree/master/boston-key-party-2016/pwn/cookbook-6), [BCTF 2016-bcloud](https://github.com/ctfs/write-ups-2016/tree/master/bctf-2016/exploit/bcloud-200) | | [unsorted_bin_into_stack.c](glibc_2.27/unsorted_bin_into_stack.c) | <a href="https://wargames.ret2.systems/level/how2heap_unsorted_bin_into_stack_2.23" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting the overwrite of a freed chunk on unsorted bin freelist to return a nearly-arbitrary pointer. | < 2.29 | [patch](https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b90ddd08f6dd688e651df9ee89ca3a69ff88cd0c)| | | [unsorted_bin_attack.c](glibc_2.27/unsorted_bin_attack.c) | <a href="https://wargames.ret2.systems/level/how2heap_unsorted_bin_attack_2.27" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting the overwrite of a freed chunk on unsorted bin freelist to write a large value into arbitrary address | < 2.29 | [patch](https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b90ddd08f6dd688e651df9ee89ca3a69ff88cd0c) | [0ctf 2016-zerostorage](https://github.com/ctfs/write-ups-2016/tree/master/0ctf-2016/exploit/zerostorage-6) | | [large_bin_attack.c](glibc_2.35/large_bin_attack.c) | <a href="https://wargames.ret2.systems/level/how2heap_large_bin_attack_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting the overwrite of a freed chunk on large bin freelist to write a large value into arbitrary address | latest | | [0ctf 2018-heapstorm2](https://dangokyo.me/2018/04/07/0ctf-2018-pwn-heapstorm2-write-up/) | | [house_of_einherjar.c](glibc_2.35/house_of_einherjar.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_einherjar_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting a single null byte overflow to trick malloc into returning a controlled pointer | latest | | [Seccon 2016-tinypad](https://gist.github.com/hhc0null/4424a2a19a60c7f44e543e32190aaabf) | | [house_of_water.c](glibc_2.36/house_of_water.c) | | Exploit a UAF or double free to gain leakless control of the t-cache metadata and a leakless way to link libc in t-cache | latest | | [37c3 Potluck - Tamagoyaki](https://github.com/UDPctf/CTF-challenges/tree/main/Potluck-CTF-2023/Tamagoyaki)| | [sysmalloc_int_free.c](glibc_2.39/sysmalloc_int_free.c) | | Demonstrating freeing the nearly arbitrary sized Top Chunk (Wilderness) using malloc (sysmalloc `_int_free()` ) | latest | | | | [house_of_orange.c](glibc_2.23/house_of_orange.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_orange_2.23" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting the Top Chunk (Wilderness) in order to gain arbitrary code execution | < 2.26 | [patch](https://sourceware.org/git/?p=glibc.git;a=blobdiff;f=stdlib/abort.c;h=117a507ff88d862445551f2c07abb6e45a716b75;hp=19882f3e3dc1ab830431506329c94dcf1d7cc252;hb=91e7cf982d0104f0e71770f5ae8e3faf352dea9f;hpb=0c25125780083cbba22ed627756548efe282d1a0) | [Hitcon 2016 houseoforange](https://github.com/ctfs/write-ups-2016/tree/master/hitcon-ctf-2016/pwn/house-of-orange-500) | | [house_of_tangerine.c](glibc_2.39/house_of_tangerine.c) | | Exploiting the Top Chunk (Wilderness) in order to trick malloc into returning a completely arbitrary pointer by abusing the tcache freelist | >= 2.26 | | [PicoCTF 2024- high frequency troubles](https://play.picoctf.org/practice/challenge/441?category=6&page=1&search=high%20frequency%20troubles) | | [house_of_roman.c](glibc_2.23/house_of_roman.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_roman_2.23" title="Debug Technique In Browser">:arrow_forward:</a> | Leakless technique in order to gain remote code execution via fake fastbins, the unsorted\_bin attack and relative overwrites. |< 2.29 |[patch](https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b90ddd08f6dd688e651df9ee89ca3a69ff88cd0c) || | [tcache_poisoning.c](glibc_2.35/tcache_poisoning.c) | <a href="https://wargames.ret2.systems/level/how2heap_tcache_poisoning_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Tricking malloc into returning a completely arbitrary pointer by abusing the tcache freelist. (requires heap leak on and after 2.32) | > 2.25 | [patch](https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=a1a486d70ebcc47a686ff5846875eacad0940e41) | | | [tcache_house_of_spirit.c](glibc_2.35/tcache_house_of_spirit.c) | <a href="https://wargames.ret2.systems/level/how2heap_tcache_house_of_spirit_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Frees a fake chunk to get malloc to return a nearly-arbitrary pointer. | > 2.25 | | | | [house_of_botcake.c](glibc_2.35/house_of_botcake.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_botcake_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Bypass double free restriction on tcache. Make `tcache_dup` great again. | > 2.25 | | | | [tcache_stashing_unlink_attack.c](glibc_2.35/tcache_stashing_unlink_attack.c) | <a href="https://wargames.ret2.systems/level/how2heap_tcache_stashing_unlink_attack_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting the overwrite of a freed chunk on small bin freelist to trick malloc into returning an arbitrary pointer and write a large value into arbitraty address with the help of calloc. | > 2.25 | | [Hitcon 2019 one punch man](https://github.com/xmzyshypnc/xz_files/tree/master/hitcon2019_one_punch_man) | | [fastbin_reverse_into_tcache.c](glibc_2.35/fastbin_reverse_into_tcache.c) | <a href="https://wargames.ret2.systems/level/how2heap_fastbin_reverse_into_tcache_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting the overwrite of a freed chunk in the fastbin to write a large value into an arbitrary address. | > 2.25 | | | | [house_of_mind_fastbin.c](glibc_2.35/house_of_mind_fastbin.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_mind_fastbin_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting a single byte overwrite with arena handling to write a large value (heap pointer) to an arbitrary address | latest | | | | [house_of_storm.c](glibc_2.27/house_of_storm.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_storm_2.27" title="Debug Technique In Browser">:arrow_forward:</a> | Exploiting a use after free on both a large and unsorted bin chunk to return an arbitrary chunk from malloc| < 2.29 | | | | [house_of_gods.c](glibc_2.24/house_of_gods.c) | <a href="https://wargames.ret2.systems/level/how2heap_house_of_gods_2.24" title="Debug Technique In Browser">:arrow_forward:</a> | A technique to hijack a thread's arena within 8 allocations | < 2.27 | | | | [decrypt_safe_linking.c](glibc_2.35/decrypt_safe_linking.c) | <a href="https://wargames.ret2.systems/level/how2heap_decrypt_safe_linking_2.34" title="Debug Technique In Browser">:arrow_forward:</a> | Decrypt the poisoned value in linked list to recover the actual pointer | >= 2.32 | | | | [safe_link_double_protect.c](glibc_2.36/safe_link_double_protect.c) | | Leakless bypass for PROTECT_PTR by protecting a pointer twice, allowing for arbitrary pointer linking in t-cache | >= 2.32 | | [37c3 Potluck - Tamagoyaki](https://github.com/UDPctf/CTF-challenges/tree/main/Potluck-CTF-2023/Tamagoyaki)| | [tcache_dup.c](obsolete/glibc_2.27/tcache_dup.c)(obsolete) | | Tricking malloc into returning an already-allocated heap pointer by abusing the tcache freelist. | 2.26 - 2.28 | [patch](https://sourceware.org/git/?p=glibc.git;a=commit;h=bcdaad21d4635931d1bd3b54a7894276925d081d) | | The GnuLibc is under constant development and several of the techniques above have let to consistency checks introduced in the malloc/free logic. Consequently, these checks regularly break some of the techniques and require adjustments to bypass them (if possible). We address this issue by keeping multiple versions of the same technique for each Glibc-release that required an adjustment. The structure is `glibc_<version>/technique.c`. Have a good example? Add it here! Try to inline the whole technique in a single `.c` -- it's a lot easier to learn that way. # Get Started ## Quick Setup - make sure you have the following packages/tools installed: `patchelf zstd wget` (of course also `build-essential` or similar for compilers, `make`, ...) - also, `/usr/bin/python` must be/point to your `python` binary (e. g. `/usr/bin/python3`) ```shell git clone https://github.com/shellphish/how2heap cd how2heap make clean base ./malloc_playground ``` Notice that this will link the binaries with your system libc. If you want to play with other libc versions. Please refer to `Complete Setup`. ## Complete Setup You will encounter symbol versioning issues (see [this](https://github.com/shellphish/how2heap/issues/169)) if you try to `LD_PRELOAD` libcs to a binary that's compiled on your host machine. We have two ways to bypass it. ### Method 1: link against older libc This one tells linker to link the target binary with the target libc. ```shell git clone https://github.com/shellphish/how2heap cd how2heap H2H_USE_SYSTEM_LIBC=N make v2.23 ``` This will link all the binaries against corresponding libcs. What's better is that it comes with debug symbols. Now you can play with any libc versions on your host machine. In this example, it will compile all glibc-2.23 binaries and link them with libc-2.23. You can change the number to play with other libc versions. ### Method 2: use docker This uses Docker-based approach to complie binaries inside an old ubuntu container so it is runnable with the target libc version. ```shell git clone https://github.com/shellphish/how2heap cd how2heap # the next command will prepare the target binary so it runs with # the expected libc version make base ./glibc_run.sh 2.30 ./malloc_playground -d -p # now you can play with the binary with glibc-2.30 # and even debug it with the correct symbols readelf -d -W malloc_playground | grep RUNPATH # or use checksec readelf -l -W malloc_playground | grep interpreter gdb -q -ex "start" ./malloc_playground ``` # Heap Exploitation Tools There are some heap exploitation tools floating around. ## Malloc Playground The `malloc_playground.c` file given is the source for a program that prompts the user for commands to allocate and free memory interactively. ## Pwngdb Examine the glibc heap in gdb: https://github.com/scwuaptx/Pwngdb ## pwndbg An exploitation-centric gdb plugin that provides the ability to view/tamper with the glibc heap: https://github.com/pwndbg/pwndbg ## gef Another excellent gdb plugin that provides the ability to examine the glibc heap: https://github.com/hugsy/gef ## heap-viewer Examine the glibc heap in IDA Pro: https://github.com/danigargu/heap-viewer ## Forkever Debugger that lets you set "checkpoints" as well as view and edit the heap using a hexeditor: https://github.com/haxkor/forkever ## heaptrace Helps you visualize heap operations by replacing addresses with symbols: https://github.com/Arinerron/heaptrace # Other resources Some good heap exploitation resources, roughly in order of their publication, are: - glibc in-depth tutorial (https://heap-exploitation.dhavalkapil.com/) - book and exploit samples - ptmalloc fanzine, a set of resources and examples related to meta-data attacks on ptmalloc (http://tukan.farm/2016/07/26/ptmalloc-fanzine/) - A malloc diagram, from libheap (https://raw.githubusercontent.com/cloudburst/libheap/master/heap.png) - Glibc Adventures: The Forgotten Chunk (https://go.contextis.com/rs/140-OCV-459/images/Glibc_Adventures-The_Forgotten_Chunks.pdf) - advanced heap exploitation - Pseudomonarchia jemallocum (http://www.phrack.org/issues/68/10.html) - The House Of Lore: Reloaded (http://phrack.org/issues/67/8.html) - Malloc Des-Maleficarum (http://phrack.org/issues/66/10.html) - some malloc exploitation techniques - Yet another free() exploitation technique (http://phrack.org/issues/66/6.html) - Understanding the heap by breaking it (https://www.blackhat.com/presentations/bh-usa-07/Ferguson/Whitepaper/bh-usa-07-ferguson-WP.pdf) - explains heap implementation and a couple exploits - The use of set_head to defeat the wilderness (http://phrack.org/issues/64/9.html) - The Malloc Maleficarum (http://seclists.org/bugtraq/2005/Oct/118) - OS X heap exploitation techniques (http://phrack.org/issues/63/5.html) - Exploiting The Wilderness (http://seclists.org/vuln-dev/2004/Feb/25) - Advanced Doug lea's malloc exploits (http://phrack.org/issues/61/6.html) - GDB Enhanced Features (GEF) Heap Exploration Tools (https://hugsy.github.io/gef/commands/heap/) - pwndbg Heap Commands (https://browserpwndbg.readthedocs.io/en/docs/commands/heap/heap/) - Painless intro to the Linux userland heap (https://sensepost.com/blog/2017/painless-intro-to-the-linux-userland-heap/) - Heap exploitation techniques that work on glibc-2.31 (https://github.com/StarCross-Tech/heap_exploit_2.31) - Overview of GLIBC heap exploitation techniques (https://0x434b.dev/overview-of-glibc-heap-exploitation-techniques/) # Hardening There are a couple of "hardening" measures embedded in glibc, like `export MALLOC_CHECK_=1` (enables some checks), `export MALLOC_PERTURB_=1` (data is overwritten), `export MALLOC_MMAP_THRESHOLD_=1` (always use mmap()), ... More info: [mcheck()](http://www.gnu.org/software/libc/manual/html_node/Heap-Consistency-Checking.html), [mallopt()](http://www.gnu.org/software/libc/manual/html_node/Malloc-Tunable-Parameters.html). There's also some tracing support as [mtrace()](http://manpages.ubuntu.com/mtrace), [malloc_stats()](http://manpages.ubuntu.com/malloc_stats), [malloc_info()](http://manpages.ubuntu.com/malloc_info), [memusage](http://manpages.ubuntu.com/memusage), and in other functions in this family. ", Assign "at most 3 tags" to the expected json: {"id":"12436","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"