Dynamically analyzing third-party application website certificates across users to detect malicious activity
A verification server provides certificate verification services to users of third-party application sites. In some embodiments, a verifier component of a user's client device provides the verification server with a certificate of a third-party application site, and the verification server indicates whether the certificate is successfully verified. In response to successful verification, the verifier component of the user's client device takes an action such as permitting the user's credentials to be provided to the third-party application site. In some embodiments, verifier components of numerous client devices provide certificates to the verification server, based on which the verification server learns which certificates are valid for a given third-party application site.
1. A non-transitory computer-readable storage medium storing executable instructions that when executed by a processor of a client device perform actions comprising:
requesting, for a user, a web page of a third-party application website;
receiving the web page and a corresponding certificate from the third-party application website;
sending, to a server by a verifier component of the client device, a representation of the certificate and an identifier of the third-party application website;
receiving an indication from the server that the representation matches a stored certificate representation of the third-party application website;
responsive to receiving the indication, permitting, by the verifier component, credentials of the user to be provided to the third-party application website;
requesting, for a user, a web page of a second third-party application website;
receiving the web page of the second third-party application website and a corresponding second certificate;
sending, to the server by the verifier component of the client device, a second representation of the second certificate and an identifier of the second third-party application website;
receiving a second indication from the server that the second representation fails to match a stored certificate representation of the second third-party application website; and
responsive to receiving the second indication:
initiating a virtual private network (VPN) connection with a trusted server,
using the VPN connection to communicate with the second third-party application website,
receiving a third certificate from the second third-party application website,
sending, to the server by the verifier component of the client device, a third representation of the third certificate and an identifier of the second third-party application website,
receiving a third indication from the server that the third representation matches a stored certificate representation of the second third-party application website, and
responsive to receiving the third indication, ceasing to use the VPN connection for communication with the second third-party application website.
2. The non-transitory computer-readable storage medium of claim 1 , the actions further comprising computing a fingerprint of the certificate as the certificate representation.
3. The non-transitory computer-readable storage medium of claim 1 , wherein the verifier component is a web browser plugin.
4. The non-transitory computer-readable storage medium of claim 1 , wherein the client device is a smartphone, and the verifier component is a security application installed on the smartphone.
5. A computer-implemented method performed on a client device, the computer-implemented method comprising:
requesting, for a user, a web page of a third-party application website;
receiving the web page and a corresponding certificate from the third-party application website;
sending, to a server by a verifier component of the client device, a representation of the certificate and an identifier of the third-party application website;
receiving an indication from the server that the representation matches a stored certificate representation of the third-party application website;
responsive to receiving the indication, permitting, by the verifier component, credentials of the user to be provided to the third-party application website;
requesting, for a user, a web page of a second third-party application website;
receiving the web page of the second third-party application website and a corresponding second certificate;
sending, to the server by the verifier component of the client device, a second representation of the second certificate and an identifier of the second third-party application website;
receiving a second indication from the server that the second representation fails to match a stored certificate representation of the second third-party application website; and
responsive to receiving the second indication:
initiating a virtual private network (VPN) connection with a trusted server, using the VPN connection to communicate with the second third-party application website,
receiving a third certificate from the second third-party application website,
sending, to the server by the verifier component of the client device, a third representation of the third certificate and an identifier of the second third-party application website,
receiving a third indication from the server that the third representation matches a stored certificate representation of the second third-party application website, and
responsive to receiving the third indication, ceasing to use the VPN connection for communication with the second third-party application website.
6. The computer-implemented method of claim 5 , further comprising computing a fingerprint of the certificate as the certificate representation.
7. The computer-implemented method of claim 5 , wherein the verifier component is a web browser plugin.
8. The computer-implemented method of claim 5 , wherein the client device is a smartphone, and the verifier component is a security application installed on the smartphone.
9. A computer system comprising:
a computer processor; and
a non-transitory computer-readable storage medium storing executable instructions that when executed by the computer processor perform actions comprising:
requesting, for a user, a web page of a third-party application website;
receiving the web page and a corresponding certificate from the third-party application website;
sending, to a server by a verifier component of the computer system, a representation of the certificate and an identifier of the third-party application website;
receiving an indication from the server that the representation matches a stored certificate representation of the third-party application website;
responsive to receiving the indication, permitting, by the verifier component, credentials of the user to be provided to the third-party application website;
requesting, for a user, a web page of a second third-party application web site;
receiving the web page of the second third-party application website and a corresponding second certificate;
sending, to the server by the verifier component of the computer system, a second representation of the second certificate and an identifier of the second third-party application website;
receiving a second indication from the server that the second representation fails to match a stored certificate representation of the second third-party application website; and
responsive to receiving the second indication:
initiating a virtual private network (VPN) connection with a trusted server,
using the VPN connection to communicate with the second third-party application website,
receiving a third certificate from the second third-party application website,
sending, to the server by the verifier component of the computer system, a third representation of the third certificate and an identifier of the second third-party application website,
receiving a third indication from the server that the third representation matches a stored certificate representation of the second third-party application website, and
responsive to receiving the third indication, ceasing to use the VPN connection for communication with the second third-party application website.
10. The computer system of claim 9 , the actions further comprising computing a fingerprint of the certificate as the certificate representation.
11. The computer system of claim 9 , wherein the verifier component is a web browser plugin.
12. The computer system of claim 9 , wherein the computer system is a smartphone, and the verifier component is a security application installed on the smartphone.