OTP/SMS Flood Attack


What’s on this page
We have received multiple reports regarding the growing threat of OTP/SMS flood attacks targeting businesses in the Kingdom of Saudi Arabia (KSA). Attackers are exploiting SMS interfaces to send a large volume of One-Time Passwords (OTPs) or SMS messages to overwhelm the host servers, potentially denying access to legitimate services.

An OTP (One-Time Password) flood attack is a type of Denial-of-Service (DoS) attack that targets the corporate website's contact form, which often includes a field for users to enter their phone number or email address.
Here's how it works:
- The attacker uses automated software or a botnet to send a large volume of messages to the website's contact form, filling in the phone number field with a fake or random entry.
- The website's server receives a flood of incoming requests, each containing a fake or random phone number. The server attempts to process each request.
- The flood of incoming requests can overwhelm the website's server, causing it to slow down or crash, potentially leading to a denial of service for legitimate users.
In some cases, the flood of incoming requests can cause additional strain on the website's server, leading to increased data usage, additional charges, or other financial harm.
POSSIBLE IMPACT
SMS flood attacks can be disruptive and damaging for businesses, leading to loss of productivity, revenue, and reputation. It is important for businesses to have robust cybersecurity measures in place to prevent and mitigate the impact of such attacks. The possible impact may include but is not limited to:
- Poor website performance due to high CPU and memory usage
- Leakage of users’ data and loss of customers trust
- Account hacking and fraudulent transactions
- Disruption of business operations
RECOMMENDATIONS
To mitigate an OTP flood attack, there are a few key measures you can take:
Implement rate limiting: To prevent an attacker from overwhelming the system with a large number of OTP requests, you can implement rate limiting on the number of requests per user or IP address. This can help to prevent a single user from generating too many requests and causing a DoS.
Implement CAPTCHAs or other challenge-response mechanisms: To prevent automated bots from generating a large number of OTP requests, you can implement CAPTCHAs or other challenge-response mechanisms that require the user to pass a robot check.
Monitor system logs: Regularly monitoring system logs can help you detect and respond to suspicious activities, such as a large number of OTP requests from a single user or IP address.
Educate users: Providing users with information about OTP flood attacks and how to protect themselves can help to prevent successful attacks. This can include information on how to recognize suspicious requests and how to report them to the service provider. In many of these cases, a business may choose to leverage the use of an SMS/OTP gateway service to manage these operations.
- A gateway may have guards in place to account for many cases of abuse that can happen against these operations (sending, etc..). They allow to set of budget limits or limit the number of messages per second, minute, hour, or day.
- On the other hand, an application communicating with an SMS gateway should implement a few guards itself in case some restrictions are not applicable. Digital forms that precede requests heading for the SMS gateway should not allow for replay attacks as well as brute force attacks, by use of a CSRF token and/or CAPTCHAs.
- There should be ways to detect any such attempt of attacks as well as to mitigate any implications that may follow.
- When such attacks are detected, offending IP addresses should be blocked from communicating with the applications. The use of WAF appliances can also help reduce the chance of the risk of web application attacks.
- Use two-factor authentication: Two-factor authentication provides an additional layer of security and can help prevent unauthorized access to accounts.
By implementing the above measures, you can reduce the risk of an OTP flood attack and help protect your users and your business from the negative impact of such attacks.
Recent Blogs

A browser-in-the-browser (BitB) attack - Cyber Advisory
A Browser-in-the-Browser (BitB) attack is a sophisticated cyber threat involving injecting malicious code into a victim's web browser.
Threat Overview:
This code creates a secondary browser within the victim's existing browser, allowing the attacker to manipulate web content, intercept network requests, and potentially gain control over the victim's browser and system. Understanding the BitB attack is crucial for organizations to develop effective mitigation strategies.

Once the website is opened, it appears as shown above (this will be the first step).

After enforcing the Full-screen display mode, only the inner browser will appear with the customized URL by the attacker.
Real-Case Scenarios of BitB Attacks:
CTM360 recently observed ongoing attack campaigns utilizing the BitB technique targeting ministries and government websites, specifically the interior ministries.
In the previously mentioned scenario, the official website of MOI Singapore remains unaffected and secure. However, the threat actor is carrying out a phishing attack by creating a fake website. Within this fraudulent site, instead of using traditional phishing methods, such as fake forms or malicious content, the attacker employs a fake browser interface within the phishing site, which appears to be the genuine site for MOI. When the victim accesses the site, they are presented with a full-screen display mode of this embedded browser, which tricks them into submitting their sensitive information.
Attack Methodology
To execute a Browser-in-the-Browser (BitB) attack, the attacker employs tactics to lure the user into visiting a malicious or compromised website. This website contains a phishing page hosted on the attacker's server. The phishing page utilizes JavaScript code to create a simulated browser window, simulating the appearance and behavior of a legitimate browser window. Within this simulated window, various types of fraudulent activities can be displayed.
Moreover, the simulated window displays a URL of the attacker's choice, such as https://accounts.google.com or https://login.microsoftonline.com. This is achieved by modifying the simulated address bar of the pop-up window using JavaScript. It may appear to the user that the specified URL is loaded within the pop-up window, but in reality, it is only shown as an image or text. The user may not notice the absence of SSL certificates or other security indicators typically present in a genuine browser window due to the full-screen display mode, which blocks the appearance of the main website’s URL due to the full-screen display model.
If the user falls victim to the BitB attack and enters their login credentials into the fake login form, the information is sent to the attacker's server via an AJAX request or a concealed form submission. Subsequently, the attacker gains access to the user's account on the legitimate service or proceeds with additional malicious activities such as identity theft or account takeover.
Potential Threats
Browser-in-the-Browser (BitB) attacks pose several potential threats and risks to victims. Here are some of the common threats associated with BitB attacks:
- Data Theft: Attackers can exploit BitB attacks to steal sensitive information, such as login credentials, financial details, personal data, or intellectual property. This stolen data can be used for identity theft, financial fraud, or sold on the dark web.
- Account Takeover: By manipulating the victim's browser and intercepting login credentials, BitB attacks can lead to unauthorized access to the victim's online accounts. Attackers may gain control over email accounts, social media profiles, online banking, or other services, enabling them to impersonate the victim or perform malicious activities.
- Malware Distribution: BitB attacks can be used as a vector to distribute malware onto the victim's system. The secondary browser created by the attacker can be used to download and execute malicious software, potentially leading to further compromise of the victim's device and sensitive data.
- Phishing and Social Engineering: Attackers can utilize BitB attacks to create convincing phishing scenarios. By simulating legitimate websites or services, they trick users into entering their login credentials or other sensitive information, which the attacker then captures and exploits.
Mitigation
The BitB attack is a tricky and risky phishing technique that can trick even careful users and bypass typical security measures. However, there are steps you can take to protect yourself from this attack:
- Be cautious of full-screen prompts: Exercise caution if a website unexpectedly opens a full-screen prompt or overlay. Take a moment to assess the situation and ensure that you are interacting with a legitimate website before entering any sensitive information.
- Be vigilant about website URLs: Pay close attention to the URL before entering any sensitive information. Check for any discrepancies or variations in the domain name or spelling that may indicate a phishing site.
- Pay attention to the details of the pop-up window, such as the size, position, appearance, and behavior of the elements. If something looks off or unusual, you should close the window and report it.
- Use a security-focused browser extension that can detect and block such phishing attempts automatically.
- Keep your browser up to date with the latest security patches and update whenever prompted by your browser.
- Make sure you have 2FA enabled for all of your critical services.
CTM360 is actively monitoring this phishing campaign and taking the necessary action by disrupting the attack and suspending the malicious site/domain. If you encounter any of such malicious sites, please report it to business@ctm360.com.
References

Navigating The Risks Of ChatGPT On Financial Institutions
What is ChatGPT?
ChatGPT, an advanced AI language model created by OpenAI, is gaining popularity and attention for its ability to generate human-like responses to natural language input. Trained on large amounts of data, ChatGPT's context comprehension and relevant response generation have made it a popular choice for businesses seeking to enhance customer experience and operations.
Major technology corporations are making significant investments in Artificial Intelligence (AI). Microsoft, for instance, has declared that it will invest $10 billion in OpenAI and intends to merge ChatGPT into its Azure OpenAI suite. This will allow businesses to include AI assets, including DALL-E, a program that generates images, and Codex, which transforms natural language into code, in their technology infrastructure.
While ChatGPT has several benefits for financial institutions, such as improving customer service and automating certain tasks, it also carries some risks that need to be addressed. Major banks and other institutions in the US have banned the use of ChatGPT within the organization. Concerns over sensitive information being put into the chatbot.

Risks associated with incorporating ChatGPT
Let's delve into the potential risks that are currently being debated regarding the use of ChatGPT:
- Data Exposure: One potential risk of using ChatGPT in the workplace is the inadvertent exposure of sensitive data. For example, employees using ChatGPT to generate data insights and analyze large amounts of financial data could unknowingly reveal confidential information while conversing with the AI model, which could lead to breaches of privacy or security. Another known data exposure case observed is Employees could potentially expose private code if they inadvertently include confidential information in the training data. This could occur if an employee includes code snippets that contain sensitive data or proprietary information, such as API keys or login credentials.
- Misinformation: ChatGPT can generate inaccurate or biased responses based on its programming and training data. Financial professionals should be cautious while using it to avoid spreading misinformation or relying on unreliable advice. ChatGPT’s current version was only trained on data sets available through 2021. In addition, the tool pulls online data that isn’t always accurate.
- Technology Dependency: While ChatGPT offers useful insights for financial decision-making, relying solely on technology may overlook human judgment and intuition. Financial professionals may misunderstand ChatGPT's recommendations or become over-reliant on it. Thus, maintaining a balance between technology and human expertise is crucial.
- Privacy Concerns: ChatGPT gathers a lot of personal data that users, unassumingly, might provide. Most AI models need a lot of data to be trained and improved, similarly, organizations might have to process a massive amount of data to train ChatGPT. This can pose a significant risk to individuals and organizations if the information is exposed or used maliciously.
External Risks associated with ChatGPT
- Social Engineering: Cybercriminals can use ChatGPT to impersonate individuals or organizations and create highly personalized and convincing phishing emails, making it difficult for victims to detect the attack. This can lead to successful phishing attacks and increase the likelihood of individuals falling for the scam.
- Creating malicious scripts and malware: Cybercriminals can train ChatGPT on vast amounts of code to produce undetectable malware strains that can bypass traditional security defenses. By using polymorphic techniques like encryption and obfuscation, this malware can dynamically alter its code and behavior, making it challenging to analyze and identify.
Recommendations:
- Financial institutions should establish clear policies and guidelines for using ChatGPT in the workplace to safeguard confidential information and mitigate the risks of data exposure.
- Anonymized data should be used to train an AI model to protect the privacy of individuals and organizations whose data is being used.
- Specific controls should be applied to how employees use information from ChatGPT in connection with their work.
- Awareness training should be provided to Employees who have access to ChatGPT on the potential risks associated with the use of the technology, including the risks of data exposure, privacy violations, and ethical concerns.
- Restricting access to ChatGPT will limit the potential for data exposure and misuse of the technology.

CXO Fraud - Scam Emails Originating From Virgin Media, Optimum And Cox.Net
There is an ongoing scam email campaign targeting executives from prominent organizations around the world. These reported email addresses on the domains are genuine email accounts of 'Virgin Media', 'Optimum' & 'Cox communications' users' which are compromised and sold on underground forums. Scammers buy and use such accounts as they have a higher reputation compared to newly created free accounts to bypass email gateways and spam filters and also lower their risk of being detected or tracked back in a bigger BEC attack.
These accounts are compromised by threat actors via phishing emails and malware, and the issue with such accounts will persist as long as end users are not careful enough while dealing with phishing and malicious emails. Based on our previous experience in response with the hosts Virgin Media, Optimum and Cox.net which are TV and cable providers in the UK and USA. They do not investigate email accounts reported to their abuse team without the original email and header information as this is a mandatory requirement as per their abuse policies. However, once this information is provided they do take action by resetting/recovering the reported account of the original user.
Additionally, enabling strict quarantine measures on your email gateway from these domains will make you a harder target and eventually the attackers moving on to another one.
RECOMMENDATIONS
- As a precautionary measure, all email from private and/or external email addresses which contain the name of your executive staff in the "From" field may flagged.
- As part of containment, please ensure to quarantine emails from the domain @virginmedia[.]com, @optimum[.]net, @optonline[.]net, @cox[.]net, @cox[.]com
- As this type of email is tricky, it is highly recommended to conduct phishing awareness training for all employees to avoid potential risks.