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Graph/restricted-shell-bypass-via-command-injection

AntiPattern

Shell Restricted Mode Bypass

restricted-shell-bypass-via-command-injection

Restricted-shell protections fail because user-controlled command composition and environment/script state (e.g., exec wrappers, hashed BASH_CMDS, unquoted temp paths, and restricted mode checks) allow execution of arbitrary binaries, bypassing intended confinement.

Node Details

Public graph metadata

Updated7/9/2026

Connections

30 linked nodes

MATCHESSolution

Split challenge data into public metadata and private scoring data — The sandbox binds the target source repo into a temporary workspace and binds only the generated MCP config. Tension: the benchmark package path with a tmpfs mount. Outcome: Added a disable switch for environments that cannot run the sandbox.

MATCHESSolution

passing health checks but its Bash cutover and post-cutover verification scripts exited early or misreported failure — Bash cutover and post-cutover verification scripts. Tension: post-increment arithmetic such as `((elapsed++))` / `((PASS_COUNT++))`, brittle command-output parsing for npm preflight status, and exact JSON-shape assumptions for RPC verification.

MATCHESSolution

Tension: Dependabot cannot access variables in its GitHub Actions jobs, only secrets. Outcome: allowed the job to access the Docker Hardened images successfully.

MATCHESSolution

As far as functionality goes, test mode operations should work despite the accounts being in a restricted status. — For testing, the onboarding behavior differences you encountered are expected. Tension: the accounts being in a restricted status. Outcome: test mode operations should work despite the accounts being in a restricted status.

MATCHESSolution

Normally, you could have just passed the parameters to `aws` in your `CMD`, but since you're substituting environment variables, you'll need to run a shell. — you'll need to run a shell. Tension: since you're substituting environment variables. Outcome: ENTRYPOINT sh -c "aws s3 sync /build s3://${BUCKET_NAME} --delete".

MATCHESSolution

Run the student code in a restricted environment while the verification code runs in a separate un-restricted environment. Tension: there's no trust boundary between the student's function and the verification code. Outcome: Untrusted or unreliable code runs in a separate process with limited access.

MATCHESSolution

Use a real sandboxing mechanism (e.g., iframe sandboxing or other isolation) instead of relying on web components; optionally provide a reusable sandbox wrapper or enforce an API/store policy and accept risk via contracts/licensing when using user-provided components.

MATCHESSolution

Restrict or audit grants of DBA/other powerful roles to accounts that can invoke invoker-rights code, and limit who can execute invoker-rights functions (avoid granting execute to PUBLIC). Prefer safer security patterns (e.g., definer-rights with controlled privileges, or using least-privilege accounts and tightening execution grants) and apply relevant Oracle security patches/workarounds for the known invoker-rights privilege inheritance behavior.

MATCHESSolution

My solution was to allow only the user the process is running under, and deny NT AUTHORITY\NETWORK. — before the code above. Tension: At first I thought I would just deny access to NT AUTHORITY\NETWORK, but the problem is that once you set up a security descriptor, everything goes from allowed by default to denied by default. Outcome: adding this before the code above.

MATCHESSolution

For your case as a last resort, call a native function — in case previous checks they can be hooked and thus bypassed. Tension: open source solutions has been bypassed my magisk. Outcome: It's still working as of today for Magisk 24+.

MATCHESSolution

Add-MpPreference -AttackSurfaceReductionOnlyExclusions "C:\path\myApp.exe" — Open an elevated Powershell. Tension: substituting path and myApp for the target executable you have created. Outcome: create a rule to allow your app.

MATCHESSolution

You can run a container in interactive mode, and that will provide a sort of sandbox environment for you — make sure you don't mount any volumes into the container. Tension: You should then be able to mess around and not have to worry about malware. Outcome: docker run -it container.

MATCHESSolution

Use a shell wrapper only if shell metacharacters are intended, otherwise pass arguments as a command array and avoid shell parsing

MATCHESSolution

Use least-privilege permissions by granting write access only to directories and files expected to be modified

MATCHESSolution

Use the appropriate repository role that permits bypassing branch protections (and accept that it conflicts with the 'Do not allow bypassing…' setting for this scenario). Alternatively, upgrade to/enable the paid branch protection capability ('Restrict who can push to matching branches') so you can control bypass behavior per user/team.

MATCHESSolution

Use protected mode and access tokens so attempts to read protected memory raise an exception instead of exposing decrypted data

MATCHESSolution

Open PowerShell (admin), check the current execution policy with `Get-ExecutionPolicy`, and if restricted, set it for the current user to `RemoteSigned` (e.g., `Set-ExecutionPolicy -Scope CurrentUser -ExecutionPolicy RemoteSigned`), then retry the `npx` command.

MATCHESSolution

Change line 361 from `if (posixly_correct == 0 || legal_identifier(name))` to `if (legal_identifier(name))` — This ensures that variable names used as function definitions always contain only legal shell identifier characters. Tension: preventing injection of shell metacharacters. Outcome: The variable name must pass validation before being concatenated into the command string that will be parsed and executed.

MATCHESSolution

Remove or modify the early-return guard in restricted_chown() — Allow the safe path to run always when affect_symlink_referent=true.

MATCHESSolution

any commands appended after the function in the same env-var value are executed unconditionally during shell init — environment variables that begin with the literal prefix '() {' as exported function definitions during shell startup. Tension: Env vars are routinely populated from untrusted sources. Outcome: pre-auth RCE.

MATCHESSolution

Patch: Change enable.def line 165 — builtins/enable.def. Tension: This blocks enable -f even during the startup file window where restricted == 0 but restricted_shell == 1. Outcome: if ((restricted || restricted_shell) && (flags & (FFLAG|DFLAG))).

MATCHESSolution

unbounded memory allocation (DoS) — processing a crafted ELF file.

MATCHESSolution

Outcome: split server_cmd on whitespace and use execvp directly with argv[] instead of 'sh -c server_cmd'.

MATCHESSolution

The vulnerability requires post-expansion path normalization and validation. — After concatenating the home directory with the user-supplied path component (line 82). Outcome: replace the blind memcpy with a validated copy that checks for path traversal sequences, or use realpath()/canonical path functions after concatenation.

MATCHESSolution

fixed pre-bash-4.4-beta2 in variables.c:assign_hashcmd lines 1764-1785 — Bash <= 5.0 restricted shell (rbash). Tension: restricted shell (rbash) can be bypassed.

MATCHESSolution

before `ijs_invoke_server(ijsdev->IjsServer)`. Tension: This re-applies the --permit-file-write allowlist that the IJS off-ramp currently skips. Outcome: stop using `execvp("sh","-c",server_cmd)`.

MATCHESSolution

The durable fix moved function imports under a distinct env-var prefix `BASH_FUNC_name%%` — Upstream remediation evolved across multiple patches. Tension: ad-hoc string checks proved insufficient. Outcome: the function importer is a separate, dedicated parser and the general env loop never feeds attacker text to parse_and_execute.

MATCHESSolution

The vulnerability can be fixed by sanitizing the fname parameter before passing to popen(). Tension: Validate that fname contains only safe characters and reject filenames containing shell metacharacters (|, ;, &, $, backtick, etc.). Outcome: Alternatively, use posix_spawn() with execv array instead of popen() to avoid shell interpretation entirely. The most secure solution is to disable the pipe device by default and require an explicit security flag to enable it.

MATCHESSolution

Shell-quote outname in do_ed_script before the sprintf — do_ed_script() at pch.c:2399-2403. Tension: avoid shell interpretation entirely.

MATCHESSolution

Add memcmp verification when stripping CWD prefix. Tension: Both fixes prevent path-traversal attacks that exploit incomplete validation checks. Outcome: add a loop to scan the entire path for %pipe% or | character anywhere in the path, not just at the beginning.

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