Skype, Slack, other Electron-based apps can be easily backdoored originally published on Ars Technica
While making these changes required administrator access on Linux and MacOS, it only requires local access on Windows. Those modifications can create new event-based “features” that can access the file system, activate a Web cam, and exfiltrate information from systems using the functionality of trusted applications—including user credentials and sensitive data. In his demonstration, Tsakalidis showed a backdoored version of Microsoft Visual Studio Code that sent the contents of every code tab opened to a remote website.
It’s not a bug, it’s a feature
The problem lies in the fact that Electron ASAR files themselves are not encrypted or signed, allowing them to be modified without changing the signature of the affected applications. A request from developers to be able to encrypt ASAR files was closed by the Electron team without action.
Tsakalidis said that in order to make modifications to Electron apps, local access is needed, so remote attacks to modify Electron apps aren’t (currently) a threat. But attackers could backdoor applications and then redistribute them, and the modified applications would be unlikely to trigger warnings—since their digital signature is not modified.