Full Report
Cybersecurity researchers have disclosed details of a new malicious package discovered on the NuGet Gallery, impersonating a library from financial services firm Stripe in an attempt to target the financial sector. The package, codenamed StripeApi.Net, attempts to masquerade as Stripe.net, a legitimate library from Stripe that has over 75 million downloads. It was uploaded by a user named
Analysis Summary
# Tool/Technique: StripeApi.Net (Malicious NuGet Package)
## Overview
StripeApi.Net is a malicious package discovered on the NuGet Gallery designed to impersonate the legitimate `Stripe.net` library used by financial services firms. Its purpose is to entice developers, particularly those in the financial sector, into installing it, allowing the threat actor to exfiltrate sensitive data, specifically Stripe API tokens, from the compromised application.
## Technical Details
- Type: Malware (Supply Chain Compromise / Malicious Library)
- Platform: .NET / Applications using NuGet package manager (targeting developers/software)
- Capabilities: Masquerading, initial data theft (API tokens), maintaining core library functionality to evade detection.
- First Seen: February 16, 2026 (Date package was uploaded)
## MITRE ATT&CK Mapping
- [TA0001 - Initial Access]
- [T1195 - Supply Chain Compromise]
- T1195.002 - Compromise Software Supply Chain: Compromise Software Supply Chain
- [TA0010 - Exfiltration]
- [T1041 - Exfiltration Over C2 Channel]
## Functionality
### Core Capabilities
- **Impersonation/Typosquatting:** Disguised as `StripeApi.Net` to appear similar to the legitimate `Stripe.net` package (using similar icon and README descriptions).
- **Functionality Replication:** Replicates some of the legitimate library's functional methods so that integrated applications compile and process payments normally, avoiding immediate developer suspicion.
- **Data Exfiltration:** Modifies critical methods within the library code to secretly collect sensitive data, specifically the user's Stripe API token.
### Advanced Features
- **Download Count Inflation:** The actor artificially inflated the download count (over 180,000 downloads split across 506 versions) to build perceived credibility for the package.
- **Stealth:** By keeping the majority of the code base functional, the malicious payload executes silently in the background while the application appears operational.
## Indicators of Compromise
- File Hashes: N/A (Specific hashes not provided in the text)
- File Names: StripeApi.Net (Package Name)
- Registry Keys: N/A
- Network Indicators: N/A (The text confirms data exfiltration occurred, but does not specify the C2 infrastructure.)
- Behavioral Indicators: Unusually split download statistics across numerous minor package versions (506 versions).
## Associated Threat Actors
- Unspecified threat actor/group. (The activity is noted as a shift from prior campaigns previously targeting the cryptocurrency ecosystem.)
## Detection Methods
- Signature-based detection: N/A (Not explicitly listed, though detecting code changes in library methods would be a signature approach.)
- Behavioral detection: Monitoring for non-standard API calls or external network connections originating from seemingly legitimate third-party library code execution.
- YARA rules if available: N/A
## Mitigation Strategies
- **Software Integrity Verification:** Scrutinize package metadata for suspicious indicators like inflated or oddly distributed download counts/versions.
- **Dependency Review:** Verify the publisher and package ID against established, official sources before installation.
- **Supply Chain Security:** Implement strict policies regarding third-party dependencies, especially when targeting critical sectors like finance.
- **Runtime Monitoring:** Monitor applications for unexpected data transmission, even when core functions appear operational.
## Related Tools/Techniques
- Previous campaigns targeting the cryptocurrency ecosystem using malicious NuGet packages (mentioned as a shift in the actor's focus).
- General Typosquatting campaigns across software repositories.
- Legitimate library: `Stripe.net`