Ever been on a rollercoaster? Well, APIs have their ups and downs too. Today, we’re embarking on a thrilling ride through the twisty tracks of OWASP’s API Top 10 2023 list. Hold onto your hats, because our first stop is the wild world of API1:2023 Broken Object Level Authorization! 🎢
| “APIs be like…" |
🎪 The Main Attraction: BOLA
In the grand circus of APIs, there’s a trickster in town: Broken Object Level Authorization, or BOLA for short. Picture this: attackers juggling object IDs like circus performers, making them dance to their whims. These aren’t just any balls; they’re the keys to the kingdom!
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| Handling your object IDs like… |
🚧 Danger Ahead: Is Your Ride Safe?
Think of object level authorization as the safety harness on a rollercoaster. Without it, there’s a risk of flying off into the abyss. If your API is just checking shoes (user IDs) but not ensuring riders are seated correctly (object IDs), you’re in for a wild, unsafe ride.
🍿 Grab Your Popcorn: Real-World Drama
Scenario #1: In the bustling e-market, an attacker discovers a backdoor. With a little URL magic, they’re peeking into every store’s cash register. That’s not a sale; that’s a steal!
Scenario #2: Picture a futuristic car show. Cars can be controlled with a phone! But wait, an intruder just honked every horn without showing a ticket. Talk about crashing the party!
Scenario #3: At the digital library, users store their prized manuscripts. But shush! There’s a mischievous librarian who, with a little code trick, can toss any book into the fireplace. Literary arson!
🎥 Spotlight: The Social Media Mishap
Setting: A popular social media platform, “ChirpChirp”, where users can post short messages called “chirps”. Each chirp has a unique ID, and users can like, share, or delete their chirps.
The Flaw: ChirpChirp’s API endpoint for deleting chirps is /deleteChirp?chirpID=<CHIRP_ID>. The backend simply deletes the chirp corresponding to the provided CHIRP_ID without verifying if the logged-in user is the owner of the chirp.
The Exploit: Alice notices that when she deletes a chirp, her browser sends a request to /deleteChirp?chirpID=12345. Out of curiosity, she changes the chirpID in the URL to 12346, which is Bob’s chirp. To her surprise, Bob’s chirp gets deleted!
🛠️ The Code Behind the Curtain
Backend Code (Before Fix):
@app.route('/deleteChirp')
def delete_chirp():
chirp_id = request.args.get('chirpID')
Chirp.delete_by_id(chirp_id)
return "Chirp deleted!"
This code simply takes the chirpID from the URL and deletes the chirp. There’s no check to see if the logged-in user actually owns the chirp they’re trying to delete.
Backend Code (After Fix):
@app.route('/deleteChirp')
def delete_chirp():
chirp_id = request.args.get('chirpID')
chirp = Chirp.get_by_id(chirp_id)
# Check if the logged-in user is the owner of the chirp
if chirp.owner == current_user.id:
Chirp.delete_by_id(chirp_id)
return "Chirp deleted!"
else:
return "Unauthorized!", 403
With the fix, the backend first fetches the chirp and checks if the logged-in user (current_user.id) is the owner of the chirp before deleting it.
🎭 The Drama Unfolds
Alice tries her trick again. This time, when she attempts to delete Bob’s chirp, she’s greeted with an “Unauthorized!” message. The day is saved, and ChirpChirp users can chirp in peace, knowing their posts are safe from mischievous deletions.
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| Securing APIs, one endpoint at a time! |
This example underscores the importance of always verifying object ownership in API endpoints, especially when performing destructive actions.
🎡 Steer Clear: Safety Tips for the Ride
- Superhero Suits: Craft a robust authorization mechanism. It’s your cape against the villains.
- Guard the Gates: Double-check who gets to ride and who doesn’t. No free rides here!
- Mystery Tickets: Use unpredictable IDs. It’s like a secret code for an exclusive club.
- Safety Checks: Regularly inspect the tracks (tests). If there’s a loose screw, fix it before the next ride.
📚 Treasure Map: Dive Deeper
- OWASP’s Treasure Troves:
- External Chronicles:
And there you have it! In the grand carnival of APIs, always ensure your rides are safe, and the show goes on without a hitch! 🎪🔐
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| Step right up and secure your APIs! |
