fix: Address security vulnerabilities and code quality issues

[remyluslosius]

Summary

This PR addresses critical security vulnerabilities where user-controlled data was being logged without sanitization, which could lead to log injection attacks (CWE-117).

Security Fixes

• Added sanitize_for_log() function to prevent log injection attacks
• Sanitized all user-controlled data before logging in 4 files:
  • backend/app/routes/automated_fixes.py
  • backend/app/routes/system_settings.py
  • backend/app/services/authorization_service.py
  • backend/app/services/command_sandbox.py
• Prevents attackers from injecting malicious content into logs

Code Quality Improvements

• Removed unnecessary list() call on dict.keys() iteration
• Used concise \d character class instead of [0-9] in regex patterns
• Improved code readability and performance

Testing

• All logging now safely handles user input
• No functional changes to application behavior
• Security hardening only

This addresses critical security vulnerabilities reported by SonarCloud.

To address the log injection risk, we should sanitize all user-provided values before logging, including request_id. The codebase already has a utility function, sanitize_for_log, designed to remove (or escape) control characters and truncate potentially dangerous input. The fix involves wrapping request_id with sanitize_for_log wherever it is logged, specifically on line 195 and 193. Since both the log statements use request_id, and both could potentially be hit with untrusted values, it is safest and most consistent to sanitize both. This change is limited to the relevant logging calls in the approve_fix_request function, inside backend/app/routes/automated_fixes.py.

No new imports or methods are required.

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To fix the issue, we should sanitize the user-controlled request_id before including it in log messages. This can be done by passing request_id through the existing sanitize_for_log() function, which replaces problematic line breaks and limits the length. We should apply this wherever request_id is logged, specifically at line 230 (and for completeness, also at line 228 in the same function, as it is user controlled). This requires only a change to the lines constructing the logged message: wrap request_id with sanitize_for_log().

No new imports or dependencies are required—the helper is already present in the file.

The fix is to sanitize all user-controlled data before logging it. The sanitize_for_log function is already present and is used to sanitize other potentially tainted strings (like result['message']). For consistency and safety, request_id should also be passed through sanitize_for_log before being interpolated into any log strings, particularly those in warning/error messages.
Specifically: In logger.warning(f"Fix rollback failed: {request_id} - {sanitize_for_log(result['message'])}") on line 271, wrap request_id with sanitize_for_log.
No further imports or code changes are needed since the sanitizer is already defined in the file.

To fix the problem, we need to sanitize any user-controlled values included in log messages before they are written to the logs. In this case, credentials.name is interpolated into the log message and comes from user input. We should pass credentials.name through the same sanitize_for_log function used for other user-controlled fields in this file.

How to fix/where to edit:

• In file backend/app/routes/system_settings.py, on line 146, wrap credentials.name with the sanitization function.
• Similarly, check other log lines in this method that interpolate credentials.name directly (lines 134, 138, and 150) and sanitize them as well.
• Only lines 134, 138, 146, and 150 in the portion shown interpolate credentials.name directly into logger messages, so sanitize all of them for completeness and consistency.

What is needed:

• Edit calls to the logger in the range of lines 134–150 to ensure all instances of credentials.name are passed through sanitize_for_log.
• No import changes or new methods are needed, as the sanitizer already exists in this file.

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To fix the log injection vulnerability, we must ensure that the user-controllable value (credentials.name) is sanitized before being included in the log entry. This should be done by wrapping credentials.name with the pre-existing sanitize_for_log() function (as is already done elsewhere in the file for other user-inputs in log messages). This will replace problematic characters such as newlines and tabs and limit the length included in the logs, preventing log injection and improving log readability.

What to change:

• In backend/app/routes/system_settings.py, line 166, replace the usage of {credentials.name} inside the log message with {sanitize_for_log(credentials.name)}.

No new imports or function definitions are needed, as sanitize_for_log is defined at the top of this file and used elsewhere.

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To fix the issue, any user-controlled data written to logs in security-sensitive strings must be sanitized to prevent log injection. The existing helper sanitize_for_log should be called on any untrusted value interpolated into log messages, not just result.reason.
Detailed steps:

• In backend/app/services/authorization_service.py, in the log statement in check_permission where ACCESS DENIED is logged (line 125), pass user_id, action, resource.resource_type, and resource.resource_id through sanitize_for_log.
• This ensures that if any user-provided string contains newlines, tabs, or carriage returns, they are replaced, and log-aware confusion or splitting is prevented.
• Only modify the log statement; do not alter its semantics or the existing logging, as there are no external dependencies required.

[sonarqubecloud]

Quality Gate failed

Failed conditions
B Security Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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To robustly prevent log injection, all user input written to logs should be sanitized to remove control characters such as \n, \r, and \t. There is already a generic function, sanitize_for_log(), that handles these characters and additional malicious formatting (such as ANSI escape sequences), and also restricts content length. Thus, the best fix is to replace the use of sanitize_username_for_log() with sanitize_for_log() for any user input that will go into log messages, especially in places where log injection could have impact—like login logging.

Therefore, in the affected code at line 227 of backend/app/routes/auth.py, replace
logger.error(f"Login failed for {sanitize_username_for_log(request.username)}: {type(e).__name__}")
with
logger.error(f"Login failed for {sanitize_for_log(request.username)}: {type(e).__name__}")

This approach retains the correct username in the log, clearly marks it as user-controlled, and applies proper sanitization to prevent log injection. No new imports or signatures are required—the function is already imported and present.

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To robustly prevent log injection, user input written in log entries must have all newline (\n), carriage-return (\r), and tab (\t) characters (and possibly other risky characters) removed or escaped. The most effective way here is to modify sanitize_username_for_log so that after the existing character filtering, any residual control/log-breaking characters are removed or escaped, mirroring the protections in sanitize_for_log. Concretely:

• In backend/app/utils/logging_security.py, update sanitize_username_for_log to escape or remove \n, \r, and \t from the sanitized username string, ideally replacing them with their safe, escaped equivalents (like \\n, \\r, \\t), as is done in sanitize_for_log.
• This ensures that any logging using sanitize_username_for_log(...) (such as on line 310 of backend/app/routes/auth.py) receives an input that cannot break log format, regardless of upstream input sanitization.
• No code beside sanitize_username_for_log and its usages require changes if this function is now safe for all usages.

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To fix this issue, further strengthen the sanitize_id_for_log function in backend/app/utils/logging_security.py so it explicitly removes or encodes newline and carriage return characters (and potentially any other problematic control characters) after they are replaced with [FILTERED]. This will ensure that even if an attacker submits an input containing such characters, they cannot inject new log entries or break log parsing.

The improvement involves:

• In sanitize_id_for_log, call a helper after the initial regex substitution that replaces or removes \n, \r, and \t (and potentially other control characters) from the sanitized string.
• Optionally, replace these with visible markers like \\n, \\r, etc., or remove them entirely.
• Ensure that every log entry using user IDs is thus protected from log injection regardless of the sanitizer's regular expression.

Only need to edit backend/app/utils/logging_security.py, as the rest of the code already calls the sanitizer and its use in hosts.py is otherwise correct.

To fully avoid log injection, every user-provided input being written to logs should have all control characters (especially newlines, carriage returns, and tabs) transformed into their escaped representations (e.g., \n, \r, \t) so new log entries cannot be forged by malicious input. In this context, the sanitize_id_for_log function (in logging_security.py) currently replaces all forbidden characters with the string [FILTERED], but [FILTERED] might appear excessively or in unexpected patterns and does not explicitly escape newlines, which could lead to confusion in logs. The best way is to first replace explicit control characters (\n, \r, \t) with their escaped equivalents (e.g., \\n, \\r, \\t), then apply the rest of the restrictive filtering (still reducing to [FILTERED] for other characters). This ensures that the log entry cannot span multiple lines or insert confusing markers. The change should be made in sanitize_id_for_log in backend/app/utils/logging_security.py. The replacement should be made before the regex-based filtering step.

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To fully address log injection concerns, log entries that include user-controlled input should use a maximally strong sanitization function—such as sanitize_for_log—in addition to more specific sanitization. The function sanitize_username_for_log already provides good protection, but to ensure that no control characters slip through, it is best to pass its output through sanitize_for_log for extra defense-in-depth.

Fix steps:

• Modify the logger call in line 230 of backend/app/services/mfa_service.py to apply sanitize_for_log to the already-sanitized username output.
• This composes both sanitization strategies, ensuring newlines, carriage returns, tabs, and other control characters (in case any remain) cannot be injected.
• No new imports are needed; both functions are available via from ..utils.logging_security import sanitize_username_for_log, sanitize_for_log.
• Only the logger statement should be changed.

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To fix the problem, the sanitation of the username needs to explicitly handle and neutralize all log control characters such as newline (\n), carriage return (\r), and tab (\t). The best way to accomplish this is to update sanitize_username_for_log in backend/app/utils/logging_security.py to replace or escape these specific characters, in addition to the existing regex filtering.

• General fix: Enhance the sanitize_username_for_log function to apply control character replacement (e.g., replacing \n with \\n, \r with \\r, \t with \\t) before the regex filtering step.
• Implementation: In sanitize_username_for_log, after converting the username to a string, apply .replace("\n", "\\n").replace("\r", "\\r").replace("\t", "\\t") to the username string. Then continue with regex filtering as before.
• Region to change: Lines 113–122 in backend/app/utils/logging_security.py.
• Additional requirements: No imports are needed, as only string operations are involved and are already in use.

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