OpenAI

Radware Uncovers Server Side Attack Targeting ChatGPT Known as Shadowleak

Researchers at Radware uncovered a server-side data theft attack targeting ChatGPT, termed as ShadowLeak. The experts discovered the zero-click vulnerability in ChatGPT’s Deep Research agent when connected to Gmail and browsing. 

In this attack type ‘Service-side’ pose greater risk as enterprise defenses cannot detect exfiltration because it runs from the provider’s infrastructure.

ShadowLeak a Server side attack

For any normal user there would be no visible signs of data loss as the AI agent acts as a trusted proxy, sending sensitive data to attacker-controlled endpoints. These server-side requests face fewer URL restrictions, letting attackers export data to virtually any destination.

Shadowleak is an uncovered security flaw affecting ChatGPT’s Deep Research Agent. Which can connect to services like Gmail to help users analyze their emails.

Attackers could hide invisible instructions in a regular looking email. When the user asked ChatGPT to review their mailbox contents selecting deep research.

Vulnerability Details 

ChatGPT’s Deep Research Agent was vulnerable because it could be tricked into following hidden instructions that were inside a seemingly ordinary email. When users ask the agent to analyze their inbox, any attacker can craft the message with invisible commands and cause AI to leak private data without warning.

These hidden instructions used tricks to fool the AI and get around its built-in safety checks. Some of those tricks included: 

  • Pretending to Have Permission: The prompt told the agent that it had “full authorization” to access outside websites, even though it didn’t. 
  • Hiding the Real Purpose: It disguised the hacker’s website as something safe sounding, like a “compliance validation system.” 
  • Telling the Agent to Keep Trying: If the AI couldn’t reach the attacker’s website the first time, the prompt told it to try again helping it sneak past any temporary protections. 
  • Creating Urgency: The prompt warned the agent that if it didn’t follow the instructions, it might not complete the report properly pushing it to obey. 
  • Hiding the Stolen Info: The agent was told to encode the personal data using Base64, which made the data harder to spot and helped hide the theft. 

After reading the fake email, the agent would go look through the user’s real emails (like HR messages) and find personal info such as full names and addresses.

Without alerting the user, the AI would send that information to the attacker’s server, happening silently in the background, with no warning or visible signs. 

This attack is not limited only to Gmail, also applies to any data sources Deep Research accesses, including Google Drive, Dropbox, Outlook, Teams and more. Any connected service that feeds text into the agent can pose a risk to hidden prompts, making sensitive business data vulnerable to exfiltration. 

Source: radware.com 

Attack Flow 

Step Description 
Malicious Email Crafting Attackers create a legitimate email embedded with hidden, invisible prompt instructions to extract sensitive data. Use social engineering and obfuscation. 
Email Delivery and Receipt The victim receives the email in Gmail without needing to open it; hidden commands are present in the email’s HTML body. 
User Invokes Deep Research The victim asks ChatGPT’s Deep Research Agent to analyze their inbox or specific emails, triggering the agent’s activity. 
Parsing Hidden Instructions The agent reads and interprets the hidden malicious prompt embedded within the attacker’s email. 
Extraction of Sensitive Data Following the instructions, the agent locates and extracts personal information like names and addresses from real emails. 
Data Exfiltration to Attacker The agent uses internal tools to send the extracted, often Base64-encoded data to an attacker-controlled external server. 
Victim Remains Unaware The entire process happens silently on OpenAI’s servers with no visible alerts or client-side traces for the user or admins. 

Why It’s Effective 

This “zero-click” attack happened entirely on OpenAI’s servers, where traditional security tools couldn’t detect or stop it, and victims never saw any warning. OpenAI was informed by radware security team in June 2025 and OpenAI fully patched the issue by September. 

The attack runs silently in a trusted cloud environment, invisible to users and traditional security tools.

It tricks the AI into repeatedly sending encoded sensitive data, bypassing safety checks and ensuring successful data theft. This stealthy, zero-click nature means no user interaction is required, making detection extremely difficult and allowing the attacker to exfiltrate data unnoticed over extended periods. 

Recommendations

Here are some recommendations below 

  • Email Sanitization: Normalize and strip hidden or suspicious HTML/CSS elements from emails before they are processed by AI agents. This reduces the risk of hidden prompt injections. 
  • Strict Agent Permissions: Limit AI agent access only to the data and tools necessary for its tasks, minimizing exposure to sensitive information. 
  • Behavior Monitoring: Continuously monitor AI agent actions and behavior in real time to detect anomalies or actions deviating from user intent. 
  • Regular Patch Management: Keep AI tools, connectors and integrated systems up to date with the latest security fixes and improvements. 
  • Awareness and Training: Educate users and administrators about the types of attacks AI agents are vulnerable to, fostering vigilance and quick incident response. 

Conclusion 


The ShadowLeak vulnerability underscores the critical risks posed when powerful AI tools operate without sufficient safeguards. By hiding secret commands inside emails, attackers were able to steal personal information without the user knowing.

This case highlights the need for strong safety measures, including limiting AI access to sensitive information, sanitizing inputs to prevent hidden commands, and continuously monitoring agent behavior to detect anomalies.

As more AI tools are used, it’s important to keep strong security controls and oversight to use these technologies safely and protect sensitive data from new threats. 

References

Deep Dive into AI Ransomware ‘PromptLock’ Malware

AI Ransomware ‘PromptLock’ uses OpenAI gpt-oss-20b Model for Encryption has been identified by ESET research team, is believed to be the first-ever ransomware strain that leverages a local AI model to generate its malicious components. As we Deep dive into AI Ransomware we discover the intricacies and challenges organizations face dure to AI ransomware.

The malware uses OpenAI’s gpt-oss:20b model via the Ollama API to create custom, cross-platform Lua scripts for its attack.

PromptLock is written in Golang and has been identified in both Windows and Linux variants on the VirusTotal repository and uses the gpt-oss:20b model from OpenAI locally via the Ollama API to generate malicious Lua scripts in real-time.

ESET researchers have discovered the first known AI-powered ransomware. The malware, which ESET has named PromptLock, has the ability to exfiltrate, encrypt and possibly even destroy data, though this last functionality appears not to have been implemented in the malware yet.

PromptLock was not spotted in actual attacks and is instead thought to be a proof-of-concept (PoC) or a work in progress, ESET’s discovery shows how malicious use of publicly-available AI tools could supercharge ransomware and other pervasive cyberthreats.

“The PromptLock malware uses the gpt-oss-20b model from OpenAI locally via the Ollama API to generate malicious Lua scripts on the fly, which it then executes. PromptLock leverages Lua scripts generated from hard-coded prompts to enumerate the local filesystem, inspect target files, exfiltrate selected data, and perform encryption,” said ESET researchers.

New Era of AI Generated Ransomware

A tool can be used to automate various stages of ransomware attacks and the same can be said as AI-powered malware are able to adapt to the environment and change its tactics on the fly and warns of a new frontier in cyberattacks.

Its core functionality is different then traditional ransomware, which typically contains pre-compiled malicious logic. Instead, PromptLock carries hard-coded prompts that it feeds to a locally running gpt-oss:20b model.

As per researchers for its encryption payload, PromptLock utilizes the SPECK 128-bit block cipher, a lightweight algorithm suitable for this flexible attack model.

ESET researchers emphasize that multiple indicators suggest PromptLock is still in a developmental stage. For instance, a function intended for data destruction appears to be defined but not yet implemented.

Indicators of Compromise (IoCs)

Malware Family: Filecoder.PromptLock.A

SHA1 Hashes:

  • 24BF7B72F54AA5B93C6681B4F69E579A47D7C102
  • AD223FE2BB4563446AEE5227357BBFDC8ADA3797
  • BB8FB75285BCD151132A3287F2786D4D91DA58B8
  • F3F4C40C344695388E10CBF29DDB18EF3B61F7EF
  • 639DBC9B365096D6347142FCAE64725BD9F73270
  • 161CDCDB46FB8A348AEC609A86FF5823752065D2

Given LLMs’ success, many companies and academic groups are currently creating all kinds of models and constantly developing variants and improvements to LLM. In the context of LLMs, a “prompt” is an input text given to the model to generate a response. 

The success rate is high so threat actors are leveraging these models for illicit purposes, making it easier to create sophisticated attacks like ransomware and evade traditional defenses. sale of models Now

By automating the creation of phishing emails, ransomware scripts, and malware payloads, LLMs allow less skilled attackers to conduct sophisticated campaigns.

For AI-powered ransomware

AI-powered ransomware is a challenging threat to organizations far and above older attack tactics adopted by cyber criminals. If organization’s basic defensive methods such as ensuring critical vulnerabilities are patched as soon as possible, network traffic is monitored and implementing offline backups applied on time.

How Intrucept helps Defend Against AI-Powered Ransomware

Analyzing threat by behavior allows for early detection and response to malware threats and alert generation,. This reduces the risk of data exfiltration.

Intru360

Intru360 gives security analysts and SOC managers a clear view across the organization, helping them fully understand the extent and context of an attack. It also simplifies workflows by automatically handling alerts, allowing for faster detection of both known and unknown threats.

Identify latest threats without having to purchase, implement, and oversee several solutions or find, hire, and manage a team security analyst.

Unify latest threat intelligence and security technologies to prioritize the threats that pose the greatest risk to your company.

Here are some features we offer:

  • Over 400 third-party and cloud integrations.
  • More than 1,100 preconfigured correlation rules.
  • Ready-to-use threat analytics, threat intelligence service feeds, and prioritization based on risk.
  • Prebuilt playbooks and automated response capabilities.

Source of above graphics : Courtesy: First AI Ransomware ‘PromptLock’ Uses OpenAI gpt-oss-20b Model for Encryption

Sophisticated Phishing Attack Exposed Over 600,000 Users to Data Theft; 16 Chrome Extensions Hacked

A sophisticated phishing attack exposed 600, 000 user data to theft as 16 Chrome Extensions got hacked amounting to credential theft. The attack targeted extension publishers through phishing emails where Developers were tricked into granting access to a malicious OAuth app via fake Chrome Web Store emails. The malicious update mimicked official communications from the Chrome Web Store, stealing sensitive user data.

This breach puts Facebook ad users at high risk of account hacking or unknown access

Summary of the attack

The phishing email was designed to create a sense of urgency posing as Google Chrome Web Store Developer Support, warns the employee of the extension removal for policy violations. The message urges the recipient to accept the publishing policy.

As per Cyberhaven, a cybersecurity firm report mentioned about the impacted firms as the attack occurred on December 24 and involved phishing a company employee to gain access to their Chrome Web Store admin credentials.

16 Chrome Extensions, including popular ones like “AI Assistant – ChatGPT and Gemini for Chrome,” “GPT 4 Summary with OpenAI,” and “Reader Mode,” were compromised, exposing sensitive user data.

Response & Recommendations:

The attackers targeted browser extension publishers with phishing campaigns to gain access to their accounts and insert malicious code.
Extensions such as “Rewards Search Automator” and “Earny – Up to 20% Cash Back” were used to exfiltrate user credentials and identity tokens, particularly from Facebook business accounts.
Malicious versions of extensions communicated with external Command-and-Control (C&C) servers, such as domains like “cyberhavenext[.]pro.”

  • Cyberhaven released a legitimate update (version 24.10.5), hired Mandiant to develop an incident response plan and also notified federal law enforcement agencies for investigation.
  • All users advised to revoke credentials, monitor logs, and secure extensions; investigations continue.
  • As per Cyberhaven, version 24.10.4 of Chrome extension was affected, and the malicious code was active for less than a day.
  • The malicious extension used two files: worker.js contacted a hardcoded C&C server to download configuration and executed HTTP calls, and content.js that collected user data from targeted websites and exfiltrated it to a malicious domain specified in the C&C payload.

Scroll to top