Last month, as I was leaving a shopping mall parking lot in Istanbul, I noticed an extra sticker on the parking machine at the payment point. I usually pay via a mobile app, so I don’t pay much attention to these machines, but that day there was a problem with the app. When I scanned the QR code on the sticker, a payment page opened that looked similar to my bank’s mobile app, but with minor differences. At first glance, it seemed normal, but upon closer inspection, I realized the domain name was different from the official bank address. This was a “quishing” attempt, a QR code scam, and it once again showed how careful we need to be in the physical world.
QR code phishing, or quishing, is when users are directed to malicious websites, fake applications, or phishing pages via QR codes they scan with their mobile devices. These attacks are typically designed to steal bank details, credit card numbers, or personal data. Fake stickers placed in places we frequently use and consider reliable in our daily lives, such as parking machines, are one of the most insidious and effective ways of such scams, because users tend to transfer the trust they have in a physical machine to a sticker on that machine.
What is Quishing and Why is It So Dangerous?
Quishing is a term derived from the combination of “QR code” and “phishing,” describing phishing attacks carried out using QR codes. These attacks are executed via fake QR codes placed on printed materials, emails, websites, or physical objects. When users scan these codes with their phones, they are unknowingly redirected to a malicious URL. This URL aims to steal personal information, bank account details, or passwords by appearing to be a legitimate site.
The danger of such scams stems from the ease of use and widespread adoption of QR codes. While we might think twice before clicking a link in an email, scanning a QR code to access a menu in a restaurant or pay at a parking machine has become so instinctive that we often don’t even check where we’re being redirected. Furthermore, on mobile devices, it’s generally harder to see the full URL or check certificate information compared to desktop browsers. This makes it easier for malicious actors to make fake sites more convincing. I read that quishing attacks globally increased by 51% last year, which highlights the seriousness of the issue.
The Parking Machine Scenario: How a Fake Sticker Works
The fake QR code scenario on a parking machine is one of the most practical and effective applications of quishing. In this method, scammers first identify the target parking machine or payment point. Then, they prepare a fake sticker designed to resemble the original payment label, with a QR code that redirects to a malicious URL. This sticker is usually placed over the machine’s existing QR code or payment instructions. Sometimes, it’s added to an empty surface of the machine with a title like “Scan for Mobile Payment.”
The operation of this scenario is quite simple. After parking your car, you come to the machine to pay. If you don’t have a mobile app or don’t want to use the physical payment methods on the machine, you opt for the QR code option. You scan the sticker you see on the machine, and the web page that opens on your phone asks you to enter your credit card information to pay the parking fee. If you’re not careful, all the information you enter goes directly into the hands of the scammers, and unauthorized charges can be made to your card. In a client project, we conducted a risk analysis on how a similar vulnerability could be used in the entry-exit automation system of a logistics center; I saw once again how critical physical access control is.
graph TD;
A["User Arrives at Parking Machine"] --> B["Sees QR Code Sticker on Machine"];
B --> C{Is Sticker Original?};
C -- No (Fake) --> D["User Scans Fake QR Code"];
C -- Yes (Original) --> E["User is Directed to Secure Payment Page"];
D --> F["Fake Payment Page Opens (Phishing Site)"];
F --> G{"Does User Enter Information?"};
G -- Yes --> H["Information Transmitted to Scammers"];
G -- No --> I["User Notices and Cancels Transaction"];
H --> J["Financial Loss / Identity Theft"];
I --> K["Searches for Secure Payment Method"];How to Distinguish Reliable QR Codes?
Distinguishing reliable QR codes from fake ones is not always easy, especially in the physical world. However, based on my experiences and security practices, I’ve identified a few critical checkpoints. First, before scanning a QR code, always carefully examine the surface where the code is placed and the sticker itself. If the sticker shows signs of wear, wrinkles, double layers, or adhesive residue, this could be a sign of a fake sticker. Original QR codes are usually printed as part of the machine or product; they are not pasted on afterwards.
Second, after scanning the QR code, always check the URL of the web page that opens on your phone. Banks, payment systems, or official institutions’ websites always have a known and reliable domain name (e.g., bankname.com.tr, paymentplatform.com). If the URL has typos, extra characters (e.g., bankname-secure.com or bankname.net), or an unrecognized domain extension (e.g., .xyz, .top), this is definitely a sign of a scam. When designing the backend for the financial calculators of one of my side products, I set up a mechanism that constantly checks domain name validity and SSL certificate validity; these checks are simple but very effective.
Third, never blindly trust a website that asks for your personal or financial information. If a parking payment site unexpectedly asks for too much information or has a strange interface, hesitate. Most legitimate payment systems only ask for the minimum necessary information. For example, banking apps usually direct you to their own secure environments and do not ask you to enter your password or card details directly on a web page. If in doubt, choose to pay by another method or use the official mobile app of the relevant institution.
Individual Protection Methods Against Quishing Attacks
There are some practical measures we can take to protect ourselves from quishing attacks. First and foremost, always be vigilant and approach with skepticism. We should treat every QR code we encounter in our daily lives, especially in situations requiring payment or personal information, as a potential risk. Even on my anonymous Turkey data platform, I added multi-factor authentication steps to protect user login information, because even the smallest vulnerability can lead to big problems.
Second, choose your QR code scanner app wisely. Some third-party scanner apps can show you a preview of the URL before opening it or warn you against malicious sites. If you’re using your phone’s built-in camera app, make it a habit to carefully check the URL that opens after scanning. If possible, prefer to pay directly using the relevant institution’s own mobile app. For example, if a mobile app is available for a parking spot, it’s much safer to open the app directly and enter the license plate to pay, rather than using a QR code.
Third, increase your general awareness of phishing. Quishing is just a variant of phishing. Just as we question the authenticity of links or messages received via email, SMS, or other platforms, we should evaluate QR codes in the physical world with the same diligence. Regularly changing your passwords and using two-factor authentication (2FA) largely prevents stolen information from being misused. I once observed in a project that unauthorized access attempts decreased by more than 90% with the implementation of 2FA; that number was truly striking.
The Evolution of Digital Phishing: Quishing and Beyond
Digital phishing is an ever-evolving threat. It has spread from traditional email-based attacks to different channels such as SMS (smishing), voice calls (vishing), and now QR codes (quishing). The main reason for this evolution is that scammers always target the channels people least expect or trust the most. The “tactile” trust we place in physical objects is a factor that makes quishing particularly effective. The idea that a sticker on a machine could be fake doesn’t easily occur to most of us.
My years of experience in system security and networking show that such attacks are fueled not only by technical vulnerabilities but also by the human factor. Social engineering continues to be the weakest link in the digital security chain. Therefore, it’s not enough to just take technological measures; we also need to educate ourselves and those around us about these threats. While developing my own Android spam app, I worked on algorithms to detect potential smishing attacks by analyzing the content of incoming SMS messages. Even such personal projects help us understand how creative threat actors can be.
Quishing is not limited to parking machines. I’ve also seen variations like fake Wi-Fi QR codes in cafes, fake campaign QR codes at bus stops, or even fake donation QR codes pasted on public billboards. Each uses the same basic principle in a different context: exploiting trust to direct the user to a malicious target. This indicates that even more complex and multi-channel attacks may emerge in the future.
Measures to be Taken at the Corporate Level and in Public Areas
Individual awareness alone is not enough; institutions and municipalities also need to take precautions against such quishing attacks. One of the most important things I learned while developing an ERP for a manufacturing company was that security needs to be considered end-to-end. The security of a payment machine starts not only with software or network security but also with physical access control.
First, the physical security of QR code payment systems or information panels used in public areas should be enhanced. QR code stickers on parking machines or other vending machines should be designed or protected in a way that prevents them from being easily removed and replaced. For example, QR codes could be laser-etched directly onto the machine’s casing or protected with a transparent, durable cover. Even better, difficult-to-copy stickers with security holograms or special identification numbers could be used.
Second, institutions should regularly audit the security of the QR codes they use. This means periodically checking the URLs that QR codes redirect to, and even conducting physical inspections to mitigate the risk of fake sticker placement. In penetration tests we conducted for a bank’s internal platform, we often found that physical security vulnerabilities were overlooked. For example, an audit team could check stickers on parking machines at regular intervals and intervene quickly in case of any abnormality.
Third, educating and raising user awareness is critical. Municipalities or payment system providers should prominently display warning messages like “Be careful when scanning QR codes” or “Use our official app” on both digital channels and physical payment points. Such an awareness campaign will increase users’ skepticism and make it harder for scammers. I previously measured that security warnings increased user interaction by 15% on a major Turkish e-commerce site.
# Example: Basic control mechanism for a QR code URL (pseudocode)
def check_qr_url(url_string):
known_safe_domains = ["bankaadi.com.tr", "odemeplatformu.com", "belediye.gov.tr"]
if not url_string.startswith("https://"):
print("WARNING: URL does not start with HTTPS. Not secure.")
return False
from urllib.parse import urlparse
parsed_url = urlparse(url_string)
domain = parsed_url.netloc
if domain not in known_safe_domains:
print(f"WARNING: Domain '{domain}' is not among known safe domains.")
return False
# Additionally, fake subdomain or path control can be performed
if "guvenli" in domain or "-" in domain: # simple heuristic
print(f"WARNING: Domain contains suspicious characters: {domain}")
return False
print(f"INFO: URL '{url_string}' appears secure.")
return True
# Example usage
print(check_qr_url("http://sahte-odeme.xyz/park"))
print(check_qr_url("https://bankaadi.com.tr/park-ode"))
print(check_qr_url("https://bankaadi-guvenli.com/odeme"))The simple Python pseudocode above demonstrates the basic steps that can be used to check a URL originating from a QR code. Such checks can be integrated into users’ mobile devices or into background security services.
The Importance of an End-to-End Approach in Digital Security
Quishing attacks reminded me once again how critical an “end-to-end” approach is in digital security. As someone who has worked in many areas throughout my career, from network architecture to software development, system administration to operations, I know that security vulnerabilities do not appear at a single point, but rather can be hidden in different links of a chain. Protecting only the software side of a system, while ignoring physical or social engineering vulnerabilities, is like leaving the door open.
In this context, Zero Trust architecture principles can also be applied to attacks like quishing. Always verify, least privilege, and continuous monitoring apply not only to network or server security but also to our daily digital interactions. When we scan a QR code, asking questions like “Is this code really coming from where I expect it to?” or “Does this website really look as it should?” is part of the Zero Trust mentality.
In conclusion, quishing is a new type of security threat that comes with the conveniences of the modern world. To protect against this threat, we need to both increase our individual vigilance and for institutions and technology providers to implement more robust security measures. My experience with this parking machine once again showed that even a small detail can carry a big risk, and that the digital world is not just about screens. For your safety, always remain skeptical and always verify.