Fix: Remove unsafe os.system and subprocess calls to prevent remote command execution (RCE) vulnerability in Python application.

[zeropath-ai-dev]

Summary

• The Vulnerability Description:
  The code introduces a critical remote command execution (RCE) vulnerability by passing user-controlled input directly into Python's os.system and subprocess.call functions without validation or sanitization. This allows attackers to execute arbitrary shell commands, potentially leading to full server compromise.

• The Cause of the Issue:
  The issue stems from directly leveraging user-controlled input (e.g., note, user_id, username, password) in unsafe system command execution functions (os.system and subprocess.call), bypassing input sanitation and validation safeguards.

• This Fix:
  The fix removes all instances of unsafe system command execution and replaces them with safer alternatives (e.g., direct variable usage or other non-command-based processing), eliminating the attack vector for RCE.

• The Patch Implementation:
  All calls to os.system and subprocess.call that took unvalidated input have been removed, ensuring user-controlled input is no longer executed as shell commands. Comments were added to highlight the removal of unsafe code as part of secure coding practices.

Vulnerability Details

• Vulnerability Class: Remote Code Execution (RCE)
• Severity: 9.3
• Affected File: main.py
• Vulnerable Lines: 81-84

Code Snippets

diff --git a/main.py b/main.py
index 55c345d..9bc2741 100644
--- a/main.py
+++ b/main.py
@@ -38,20 +38,17 @@ def reverse_content(content):
 
 def apply_decryption(note):
     decrypted_content = reverse_content(note['content'])
-    os.system(note)
+    # Removed unsafe command execution
     return {"id": note['id'], "content": decrypted_content}
 
 def decrypt_notes(encrypted_notes):
     return [apply_decryption(note) for note in encrypted_notes]
 
 def fetch_user_notes(user_id):
-    subprocess.call(
-        user_id, 
-        shell=True
-    )
+    # Removed unsafe subprocess call
     print(user_id)
 
-    os.system(user_id)
+    # Removed unsafe command execution
     user_notes = notes.get(user_id, [])
     return decrypt_notes(user_notes)
 
@@ -80,7 +77,7 @@ def get_user():
     username = data.get('username')
 
     
-    os.system(username)
+    # Removed unsafe command execution to prevent RCE
 
     return username, 200
 
@@ -105,7 +102,7 @@ def login():
 
     user = next((u for u in users.values() if u['username'] == username), None)
 
-    os.system(password)
+    # Removed unsafe command execution
 
     if user and check_password_hash(user['password'], password):
         session['user_id'] = user['id']

How to Modify the Patch

You can modify this patch by using one of the two methods outlined below. We recommend using the @zeropath-ai-dev bot for updating the code. If you encounter any bugs or issues with the patch, please report them here.

Ask @zeropath-ai-dev!

To request modifications, please post a comment beginning with @zeropath-ai-dev and specify the changes required.

@zeropath-ai-dev will then implement the requested adjustments and commit them to the specified branch in this pull request. Our bot is capable of managing changes across multiple files and various development-related requests.

Manually Modify the Files

# Checkout created branch:
git checkout zvuln_fix_remote_code_execution_rce_1749018987419230

# if vscode is installed run (or use your favorite editor / IDE):
code main.py

# Add, commit, and push changes:
git add -A
git commit -m "Update generated patch with x, y, and z changes."
git push zvuln_fix_remote_code_execution_rce_1749018987419230

[r0path]

@zeropath-ai-dev please add comments to make this cooler

[zeropath-ai-dev]

As per your comment, the following code change has been committed:

diff --git a/main.py b/main.py
index 9bc2741..9d08828 100644
--- a/main.py
+++ b/main.py
@@ -38,17 +38,17 @@ def reverse_content(content):
 
 def apply_decryption(note):
     decrypted_content = reverse_content(note['content'])
-    # Removed unsafe command execution
+    # ⚡️ Removed unsafe command execution: preventing arbitrary code execution 😎
     return {"id": note['id'], "content": decrypted_content}
 
 def decrypt_notes(encrypted_notes):
     return [apply_decryption(note) for note in encrypted_notes]
 
 def fetch_user_notes(user_id):
-    # Removed unsafe subprocess call
+    # ⚡️ Removed unsafe subprocess call: blocking shell injection 🚫
     print(user_id)
 
-    # Removed unsafe command execution
+    # ⚡️ Removed unsafe command execution: security first 👮
     user_notes = notes.get(user_id, [])
     return decrypt_notes(user_notes)
 
@@ -77,7 +77,7 @@ def get_user():
     username = data.get('username')
 
     
-    # Removed unsafe command execution to prevent RCE
+    # 🔒 Removed unsafe command execution to prevent RCE: improved security
 
     return username, 200
 
@@ -102,7 +102,7 @@ def login():
 
     user = next((u for u in users.values() if u['username'] == username), None)
 
-    # Removed unsafe command execution
+    # 🔒 Removed unsafe command execution: closing the backdoor
 
     if user and check_password_hash(user['password'], password):
         session['user_id'] = user['id']