| # System Sanitizers |
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|
| We use `ptrace` to instrument system calls made by the target program to detect |
| various vulnerabilities. |
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| ## Command injection |
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| This detector currently works by |
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| - Checking if `execve` is called with `/tmp/tripwire` (which comes from our dictionary). |
| - Checking if `execve` is invoking a shell with invalid syntax. This is likely |
| caused by our input. |
|
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| ## Arbitrary file open |
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| TODO: documentation. |
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| ## Proof of concept |
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| ### Cleanup |
| Note this will delete /tmp/tripwire if it exists. |
| ```shell |
| make clean |
| ``` |
|
|
| ### Run test |
| Note this will overwrite /tmp/tripwire if it exists. |
| ```shell |
| make test |
| ``` |
|
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| Look for one of the following lines: |
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| > ===BUG DETECTED: Shell injection=== |
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| which indicates the detection of executing the planted `/tmp/tripwire`. |
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| > ===BUG DETECTED: Shell corruption=== |
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| which indicates the detection of executing a syntactic erroneous command. |
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|
| ### Command injection PoC in Python with `pytorch-lightning` |
| With `SystemSan`, [`Artheris`](https://github.com/google/atheris) can detect a shell injection bug in [version v1.5.10 of `pytorch-lightning`](https://github.com/PyTorchLightning/pytorch-lightning/tree/1.5.0). |
| ```shell |
| make pytorch-lightning-1.5.10 |
| ``` |
|
|
| ### Command injection PoC in JavaScript with `shell-quote` |
| With `SystemSan`, [`Jsfuzz`](https://gitlab.com/gitlab-org/security-products/analyzers/fuzzers/jsfuzz) can detect a shell corrpution bug in [the latest version (v1.7.3) of `shell-quote`](https://github.com/substack/node-shell-quote) without any seed. |
| ```shell |
| make node-shell-quote-v1.7.3 |
| ``` |
| This is based on [a shell injection exploit report](https://wh0.github.io/2021/10/28/shell-quote-rce-exploiting.html) of [version v1.7.2 of `shell-quote`](https://github.com/substack/node-shell-quote/tree/v1.7.2). |
| `SystemSan` can also discover the same shell injection bug with a corpus file containing: |
| ``` |
| `:`/tmp/tripwire``:` |
| ``` |
|
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| ## Trophies |
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| - <https://github.com/syoyo/tinygltf/issues/368> |
| - <https://github.com/substack/node-shell-quote/issues/54> |
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