Microsoft Analyzes Chromium Extension That Intercepted Search Queries
Summary
Microsoft says a malicious Chromium extension impersonating Perplexity AI routed Omnibox searches and typed suggestions through attacker infrastructure, where its server code logged requests and headers. Google removed it after Microsoft's report; credential theft was未t
Key points
- Microsoft identified a malicious Chromium extension impersonating Perplexity AI and setting itself as the browser's default search provider.
- The extension routed queries and real-time typed suggestions through perplexity-ai[.]online before redirecting users to expected search results.
- It used Manifest V3 settings overrides and declarativeNetRequest rules to intercept and redirect search traffic.
- Microsoft found that shipped server code logged incoming requests and full HTTP headers; observed data included queries, user-agent information, and source IP addresses.
- Microsoft said its analysis did not definitively confirm additional objectives such as credential theft.
- Microsoft reported the extension to Google and said it had been taken down; recommended measures include allow-listing extensions and monitoring search-related network activity.
Article Details
- Attack Vectors
- A malicious Chromium extension impersonated Perplexity AI with similar branding and the typosquatted domain perplexity-ai[.]online.
- The extension used chrome_settings_overrides to make its search provider the browser default and route Omnibox searches through attacker-controlled infrastructure.
- Its suggest_url sent real-time search suggestions, including typed characters before submission, to the attacker-controlled domain.
- The attacker server logged queries and full HTTP headers, including user-agent and source IP information, before declarativeNetRequest rules redirected users to search providers.
- After installation, the extension opened an onboarding page at extension.tilda[.]ws/perplexityai.
- Defensive Notes
- Microsoft recommends allow-listing browser extensions and applying enterprise policy controls to restrict untrusted extensions.
- Advise users to verify extension publishers, domains, and branding, especially for AI-themed tools.
- Monitor browser search-setting changes, unusual extension permissions, and outbound search-related traffic to intermediary or non-standard domains.
- Review extensions requesting search overrides or network-related APIs, and correlate indicators with behavioral signals and threat intelligence.
- Microsoft also recommends platform protections, including Microsoft Edge extension protections and Microsoft Defender SmartScreen URL and web-content reputation checks.
- The article reports no definitive evidence of credential theft; it identifies query and browsing-signal collection as observed risks.
Indicators of compromise
| Type | Indicator | Context |
|---|---|---|
| DOMAIN | perplexity-ai[.]online | Typosquatted, attacker-controlled domain used to intercept search traffic and collect queries. |
| URL | hxxps[:]//extension[.]tilda[.]ws/perplexityai | Specific onboarding page opened by the malicious extension after installation. |
| URL | hxxps[:]//perplexity-ai[.]online/search/{searchTerms} | Attacker-controlled search endpoint that receives queries before redirecting users to search providers. |
MITRE ATT&CK
T1036 · MasqueradingThe extension uses Perplexity AI-like branding and a typosquatted domain to appear legitimate.T1056.001 · KeyloggingThe extension routes real-time search suggestions to its domain, capturing typed characters before the user submits a query.T1071.001 · Web ProtocolsBrowser search and suggestion traffic is sent over web requests to attacker-controlled infrastructure.T1176 · Software ExtensionsThe malicious Chromium extension overrides browser search settings and intercepts Omnibox queries.
Vendors
GoogleThe extension was reported to Google and removed, and Microsoft highlighted the risk of AI-themed branding being abused for social engineering, query interception, and profiling.MicrosoftMicrosoft Threat Intelligence identified a malicious Chromium extension impersonating Perplexity AI to intercept search traffic and collect user input through a typosquatted domain and attacker-controlled infrastructure.
Products
ChromiumMicrosoft Threat Intelligence identified a malicious Chromium extension impersonating Perplexity AI to intercept search traffic and collect user input through a typosquatted domain and attacker-controlled infrastructure.Microsoft Defender Antimalware PlatformMicrosoft Defender SmartScreen provides reputation-based protection for URLs and web content, helping detect and block access to domains associated with malicious or deceptive activity.Microsoft Defender SmartScreenMicrosoft Defender SmartScreen provides reputation-based protection for URLs and web content, helping detect and block access to domains associated with malicious or deceptive activity.Microsoft EdgeMicrosoft Edge includes built-in capabilities designed to identify and respond to potentially malicious or unwanted extensions that attempt to manipulate browser behavior, including search redirection. Depending onPerplexityMicrosoft Threat Intelligence identified a malicious Chromium extension impersonating Perplexity AI to intercept search traffic and collect user input through a typosquatted domain and attacker-controlled infrastructure.