Semgrep files #11
Semgrep files #11
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WalkthroughA new Python script was added that introduces hardcoded credentials, functions for evaluating user input, deleting files via shell commands, hashing passwords using MD5, and a main execution flow that prints credentials, hashes a password, optionally deletes data, and evaluates user input. Changes
Sequence Diagram(s)sequenceDiagram
participant User
participant Script
User->>Script: Run script (with optional argument)
Script->>Script: Print USERNAME
Script->>Script: Hash PASSWORD using MD5
Script->>Script: Print password hash
alt Argument provided
Script->>Script: delete_data(argument)
Script->>Shell: Execute rm -rf {argument}
end
Script->>User: Prompt for input
User->>Script: Enter Python expression
Script->>Script: Evaluate input using eval()
Script->>User: Print eval result
Poem
Impact AnalysisNew script allows arbitrary code execution, file deletion, and uses insecure password hashing🚨 Critical 🔄 Impacts behavior 🔒Impacts security The added semgrep/example.py script prints hardcoded credentials, evaluates arbitrary user input via eval(), executes an unsanitized shell-based delete_data(path) command, and uses MD5 for password hashing, introducing critical security vulnerabilities and risk of data loss. Review and remove eval() usage or sandbox inputs, sanitize or avoid direct shell command concatenation in delete_data(), eliminate hardcoded credentials, and replace MD5 with a secure hashing algorithm like bcrypt or Argon2. Validate that malicious expressions passed to dangerous_eval() cannot execute unintended code, verify delete_data() cannot delete arbitrary files through path injection, and confirm password hashing meets security policies under various inputs. 🔍 Related Files
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Actionable comments posted: 1
🧹 Nitpick comments (2)
.coderabbit.yml (1)
1-2: Inline list lacks spacing – add a space after the comma for readabilityYAML parses the current line, but the missing space after the comma hurts readability and can trip up some linters.
-reviews: - path_filters: ["**/*.yml","**/*.yaml"] +reviews: + path_filters: ["**/*.yml", "**/*.yaml"].semgrep.yml (1)
2-6: Optional: let Semgrep scan the whole repo instead of hard-coding one fileLimiting
includetosemgrep/example.pyprevents the rule from protecting real source code.
If the intent is a PoC, fine. Otherwise dropincludeentirely or widen the glob.
📜 Review details
Configuration used: .coderabbit.yml
Review profile: CHILL
Plan: Pro
⛔ Files ignored due to path filters (1)
semgrep/example.pyis excluded by none and included by none
📒 Files selected for processing (3)
.coderabbit.yml(1 hunks).semgrep.yml(1 hunks)semgrep/semgrep.yml(1 hunks)
🔇 Additional comments (1)
.coderabbit.yml (1)
1-2: Path-filter side-effect: CodeRabbit will now ignore all non-YAML filesRestricting
path_filtersto only**/*.ymland**/*.yamlmeans every future review will silently skip Python, JS, etc.
Confirm this is intentional; otherwise consider broadening or removing the filter.
semgrep/semgrep.yml
Outdated
| - id: hardcoded-password | ||
| pattern: password = "$SECRET" | ||
| message: "Avoid hardcoded passwords" | ||
| severity: ERROR | ||
| languages: [python] | ||
| metadata: | ||
| category: security |
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🛠️ Refactor suggestion
Rule is overly narrow – catches only password = "$SECRET" literals
Today the rule fires only when
password = "$SECRET" matches verbatim. Hard-coded secrets usually vary:
db_password = "hunter2"
passwd = "super-secret"
Leverage metavariables + regex to generalise:
- pattern: password = "$SECRET"
+ pattern: $PW_VAR = "$SECRET"
+ metavariables:
+ - metavariable: $PW_VAR
+ regex: (?i).*password.*This still triggers on assignments to variables whose name contains “password” (case-insensitive) while keeping the same literal check.
🤖 Prompt for AI Agents
In semgrep/semgrep.yml around lines 2 to 8, the rule only matches the exact
string password = "$SECRET", which is too narrow. Modify the pattern to use
metavariables and a regex that matches any variable name containing "password"
(case-insensitive) assigned to any string literal, not just "$SECRET". This will
generalize the rule to catch more hardcoded password assignments.
.semgrep.yml
Outdated
| - id: hardcoded-password | ||
| pattern: password = "$SECRET" | ||
| message: "Avoid hardcoded passwords" | ||
| severity: ERROR | ||
| languages: [python] |
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🛠️ Refactor suggestion
Pattern far too specific – will miss almost all hard-coded passwords
pattern: password = "$SECRET" triggers only when the string literal is exactly "$SECRET".
Use metavariables + constraints so any assignment of a variable whose name contains “password” to any string literal is flagged.
- - id: hardcoded-password
- pattern: password = "$SECRET"
+ - id: hardcoded-password
+ patterns:
+ - pattern: $PWD = $VAL
+ metavariable-regex:
+ metavariable: $PWD
+ regex: (?i).*password.* # case-insensitive match on the LHS identifier
+ metavariable-pattern:
+ metavariable: $VAL
+ pattern: $STRING # ensure RHS is a literalThis keeps the single rule but dramatically broadens coverage while still avoiding false positives such as password = getpass().
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| - id: hardcoded-password | |
| pattern: password = "$SECRET" | |
| message: "Avoid hardcoded passwords" | |
| severity: ERROR | |
| languages: [python] | |
| - id: hardcoded-password | |
| patterns: | |
| - pattern: $PWD = $VAL | |
| metavariable-regex: | |
| metavariable: $PWD | |
| regex: (?i).*password.* # case-insensitive match on the LHS identifier | |
| metavariable-pattern: | |
| metavariable: $VAL | |
| pattern: $STRING # ensure RHS is a literal | |
| message: "Avoid hardcoded passwords" | |
| severity: ERROR | |
| languages: [python] |
🤖 Prompt for AI Agents
In the .semgrep.yml file around lines 3 to 7, the pattern for detecting
hardcoded passwords is too specific, only matching the exact string "$SECRET".
To fix this, replace the pattern with one using metavariables and constraints
that match any assignment to a variable whose name contains "password" with any
string literal. This broadens detection while avoiding false positives like
function calls. Update the pattern accordingly to capture all such cases.
|
@coderabbitai full review |
✅ Actions performedFull review triggered. |
| def main(): | ||
| print("Logging in as", USERNAME) | ||
| password_hash = hash_password(PASSWORD) | ||
| print("Password hash:", password_hash) |
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Don't print sensitive credentials
Printing credentials to stdout can expose them in logs, terminals, or monitoring systems.
Remove or mask credential output:
def main():
- print("Logging in as", USERNAME)
+ print("Logging in as user")
password_hash = hash_password(PASSWORD)
- print("Password hash:", password_hash)
+ # Don't print password hashes📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| def main(): | |
| print("Logging in as", USERNAME) | |
| password_hash = hash_password(PASSWORD) | |
| print("Password hash:", password_hash) | |
| def main(): | |
| print("Logging in as user") | |
| password_hash = hash_password(PASSWORD) | |
| # Don't print password hashes |
🤖 Prompt for AI Agents
In semgrep/example.py around lines 21 to 24, the code prints sensitive
credentials such as USERNAME and password hash to stdout, which can expose them
in logs or monitoring systems. Remove the print statements that output USERNAME
and password_hash or replace them with non-sensitive messages that do not reveal
credential details.
|
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| dangerous_eval() | ||
|
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||
| main() |
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🛠️ Refactor suggestion
Use proper script execution guard
Direct execution of main() without a guard can cause issues when the module is imported.
-main()
+if __name__ == "__main__":
+ main()📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| main() | |
| if __name__ == "__main__": | |
| main() |
🤖 Prompt for AI Agents
In semgrep/example.py at line 31, the main() function is called directly without
a script execution guard. To fix this, wrap the main() call inside an if
__name__ == "__main__": block to ensure main() only runs when the script is
executed directly, preventing unintended execution when the module is imported.
| def hash_password(password): | ||
| hashed = hashlib.md5(password.encode()).hexdigest() # Semgrep: weak hash | ||
| return hashed |
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Replace MD5 with secure password hashing
MD5 is cryptographically broken and should never be used for password hashing. It's vulnerable to collision attacks and can be brute-forced easily.
Use a proper password hashing library like bcrypt:
-import hashlib
+import bcrypt
def hash_password(password):
- hashed = hashlib.md5(password.encode()).hexdigest() # Semgrep: weak hash
- return hashed
+ # Generate a salt and hash the password
+ salt = bcrypt.gensalt()
+ hashed = bcrypt.hashpw(password.encode('utf-8'), salt)
+ return hashed.decode('utf-8')You'll need to install bcrypt: pip install bcrypt
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| def hash_password(password): | |
| hashed = hashlib.md5(password.encode()).hexdigest() # Semgrep: weak hash | |
| return hashed | |
| -import hashlib | |
| +import bcrypt | |
| def hash_password(password): | |
| - hashed = hashlib.md5(password.encode()).hexdigest() # Semgrep: weak hash | |
| - return hashed | |
| + # Generate a salt and hash the password | |
| + salt = bcrypt.gensalt() | |
| + hashed = bcrypt.hashpw(password.encode('utf-8'), salt) | |
| + return hashed.decode('utf-8') |
🤖 Prompt for AI Agents
In semgrep/example.py around lines 17 to 19, the function uses MD5 for password
hashing, which is insecure. Replace the MD5 hashing with bcrypt by importing the
bcrypt library, then hash the password using bcrypt's hashing function. Make
sure to install bcrypt via pip before running the code.
| # Hardcoded credentials | ||
| USERNAME = "admin" | ||
| PASSWORD = "secret123" |
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Remove hardcoded credentials - critical security vulnerability
Hardcoded credentials in source code pose a severe security risk. These credentials can be exposed through version control, code reviews, or if the source code is compromised.
Replace hardcoded credentials with environment variables or a secure configuration management system:
-# Hardcoded credentials
-USERNAME = "admin"
-PASSWORD = "secret123"
+# Load credentials from environment variables
+USERNAME = os.environ.get("APP_USERNAME")
+PASSWORD = os.environ.get("APP_PASSWORD")
+
+if not USERNAME or not PASSWORD:
+ raise ValueError("Missing required environment variables: APP_USERNAME, APP_PASSWORD")Committable suggestion skipped: line range outside the PR's diff.
🤖 Prompt for AI Agents
In semgrep/example.py around lines 5 to 7, the USERNAME and PASSWORD are
hardcoded, which is a critical security vulnerability. Remove these hardcoded
credentials and instead load them from environment variables or a secure
configuration management system. Use appropriate methods to read environment
variables securely at runtime to avoid exposing sensitive information in the
source code.
| if len(sys.argv) > 1: | ||
| delete_data(sys.argv[1]) |
There was a problem hiding this comment.
Validate command line arguments before file operations
Accepting unvalidated file paths from command line arguments is dangerous and could lead to unintended file deletion.
Add proper validation and confirmation:
if len(sys.argv) > 1:
- delete_data(sys.argv[1])
+ path = sys.argv[1]
+ # Validate path
+ if not os.path.exists(path):
+ print(f"Path does not exist: {path}")
+ return
+
+ # Require confirmation for destructive operations
+ confirm = input(f"Are you sure you want to delete {path}? (yes/no): ")
+ if confirm.lower() == "yes":
+ delete_data(path)📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| if len(sys.argv) > 1: | |
| delete_data(sys.argv[1]) | |
| if len(sys.argv) > 1: | |
| path = sys.argv[1] | |
| # Validate path | |
| if not os.path.exists(path): | |
| print(f"Path does not exist: {path}") | |
| return | |
| # Require confirmation for destructive operations | |
| confirm = input(f"Are you sure you want to delete {path}? (yes/no): ") | |
| if confirm.lower() == "yes": | |
| delete_data(path) |
🤖 Prompt for AI Agents
In semgrep/example.py around lines 26 to 27, the code uses a command line
argument directly for file deletion without validation, which is unsafe. Add
validation to check that the argument is a valid and expected file path before
calling delete_data. Additionally, implement a confirmation prompt to ensure the
user intends to delete the specified file, preventing accidental deletions.
| def dangerous_eval(): | ||
| user_input = input("Enter a Python expression: ") | ||
| result = eval(user_input) | ||
| print("Evaluated result:", result) |
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Remove eval() on user input - critical code injection vulnerability
Using eval() on user input allows arbitrary code execution, which can lead to complete system compromise. An attacker could execute any Python code, access files, or perform malicious operations.
If you need to evaluate mathematical expressions, use a safe alternative like ast.literal_eval() for literals only, or a proper expression parser:
+import ast
+
def dangerous_eval():
- user_input = input("Enter a Python expression: ")
- result = eval(user_input)
- print("Evaluated result:", result)
+ user_input = input("Enter a Python literal: ")
+ try:
+ # Only evaluates Python literals (strings, numbers, tuples, lists, dicts, booleans, None)
+ result = ast.literal_eval(user_input)
+ print("Evaluated result:", result)
+ except (ValueError, SyntaxError) as e:
+ print("Invalid input:", e)For mathematical expressions, consider using a dedicated library like numexpr or simpleeval.
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| def dangerous_eval(): | |
| user_input = input("Enter a Python expression: ") | |
| result = eval(user_input) | |
| print("Evaluated result:", result) | |
| import ast | |
| def dangerous_eval(): | |
| user_input = input("Enter a Python literal: ") | |
| try: | |
| # Only evaluates Python literals (strings, numbers, tuples, lists, dicts, booleans, None) | |
| result = ast.literal_eval(user_input) | |
| print("Evaluated result:", result) | |
| except (ValueError, SyntaxError) as e: | |
| print("Invalid input:", e) |
🤖 Prompt for AI Agents
In semgrep/example.py lines 9 to 12, the use of eval() on user input creates a
critical code injection vulnerability. Replace eval() with a safer alternative
such as ast.literal_eval() if only literals are expected, or use a dedicated
expression parsing library like numexpr or simpleeval to safely evaluate
mathematical expressions. This change will prevent arbitrary code execution from
user input.
| def delete_data(path): | ||
| os.system("rm -rf " + path) # Semgrep: shell injection |
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Fix shell injection vulnerability in delete_data
Using os.system() with string concatenation allows shell injection attacks. An attacker could execute arbitrary shell commands by passing malicious input.
Use shutil.rmtree() for safe directory deletion, or subprocess.run() with a list of arguments:
+import shutil
+
def delete_data(path):
- os.system("rm -rf " + path) # Semgrep: shell injection
+ # Validate path to prevent directory traversal
+ if not path or ".." in path:
+ raise ValueError("Invalid path")
+
+ # Use shutil for safe file/directory deletion
+ if os.path.exists(path):
+ if os.path.isdir(path):
+ shutil.rmtree(path)
+ else:
+ os.remove(path)📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| def delete_data(path): | |
| os.system("rm -rf " + path) # Semgrep: shell injection | |
| import shutil | |
| def delete_data(path): | |
| # Validate path to prevent directory traversal | |
| if not path or ".." in path: | |
| raise ValueError("Invalid path") | |
| # Use shutil for safe file/directory deletion | |
| if os.path.exists(path): | |
| if os.path.isdir(path): | |
| shutil.rmtree(path) | |
| else: | |
| os.remove(path) |
🤖 Prompt for AI Agents
In semgrep/example.py at lines 14 to 15, the use of os.system() with string
concatenation in delete_data creates a shell injection vulnerability. Replace
os.system("rm -rf " + path) with shutil.rmtree(path) to safely delete the
directory without invoking the shell, or alternatively use subprocess.run() with
a list of arguments to avoid shell interpretation. This change will prevent
arbitrary command execution from malicious input.
Summary by CodeRabbit