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Graph/restricted-shell-bypass-via-alternate-execution-paths

AntiPattern

Shell Guard Bypass Paths

restricted-shell-bypass-via-alternate-execution-paths

Shell enforcement fails when execution/validation routes around restricted-mode logic—e.g., direct command-hash injection, fd-based stderr logging bypassing wrappers, or type checks keyed to the wrong selector—allowing arbitrary binary execution or incorrect certificate validation.

Node Details

Public graph metadata

Updated7/17/2026

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

Harden environment-derived TMPDIR usage by validating tmp is absolute/does not contain unexpected characters — environment-derived TMPDIR usage. Tension: disallow path traversal sequences if those end up used in filesystem operations. Outcome: Consider using safer formatting (snprintf into buffer) and documenting invariants for xheader_format_name / header encoding.

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

You could use a file with the secret token, placed in secure directory — as part of the bundle process. Tension: and ensure a script is run as part of the bundle process. Outcome: An example to set env variables.

MATCHESSolution

Tension: the trap is mixing default (stripping) mode with a post-parse policy check. Outcome: parse AFTER the guard.

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

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

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

GitGuardian: for secure code sharing without revealing the actual base code, ideal for sensitive information. — For technical access control irregardless of the NDA. Tension: without revealing the actual base code. Outcome: ideal for sensitive information.

MATCHESSolution

Marking a function as direct only disqualifies it from being run in those situations — trigger programs, check constraints, view definitions, etc. Outcome: it has to be directly in the SQL code that you have in your program.

MATCHESSolution

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

MATCHESSolution

Added a unit suite for the helper — Verification. Tension: the false-positive guard that a POSIX /Cabinet/... path is NOT mistaken for a drive. Outcome: the diagnostics route now accepts a { uri } payload (200) and returns 404 (not 500) for a non-string locator.

MATCHESSolution

Skip the SSO detector and switch to compiler-generated functions

MATCHESSolution

Updated the Codex harness to use current unattended flags (--dangerously-bypass-approvals-and-sandbox and --skip-git-repo-check) — The first Codex smoke failed before execution with a trusted-directory error and a deprecated --full-auto warning. Tension: preserving older event paths. Outcome: Parser smoke test recognized a sample mcp_tool_call and token usage.

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

The vulnerability requires validating that function definition variables contain ONLY a valid function definition. — Bash 4.4+ includes a proper fix by validating function definitions during the parsing phase. Tension: The parser was modified to reject function definitions that have trailing code after the closing brace.

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

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

prevents -i and -J from being used together — adding validation in tool_getparam.c. Tension: accepting filenames from HTTP headers and using rename() on them creates a symlink-attack vector. Outcome: rejects PARAM_BAD_USE when both flags are specified.

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

Refuse to dispatch OSC 83 by default — Mitigation/patch in src/ansi.c StringEnd(). Tension: the payload after the semicolon is parsed by Parse() and dispatched directly to DoCommand(). Outcome: only enter the typ==83 branch when explicitly enabled.

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

Found vulnerability through source code audit of coreutils-8.20 — key files examined: src/sort.c. Tension: the issue.

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.

MATCHESSolution

Add validation to reject any path containing ../ sequences after tilde expansion — after tilde expansion. Outcome: implement proper path normalization that prevents traversal.

MATCHESSolution

Three techniques applied together: — any enforcement module (DOM assertion, CSP checker, sanitizer) that must reference the same patterns its surrounding CI gate scans for. Tension: split the forbidden literal at any point that breaks the contiguous match without altering the runtime string value.

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