Multiple vulnerabilities in cURL



Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2021-22876
CVE-2021-22890
CWE-ID CWE-200
CWE-300
Exploitation vector Network
Public exploit N/A
Vulnerable software
 cURL
Client/Desktop applications / Other client software

Vendor curl.haxx.se

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Information disclosure

EUVDB-ID: #VU51821

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-22876

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to libcurl does not strip off user credentials from the URL when automatically populating the Referer: HTTP request header field in outgoing HTTP requests and therefore risks leaking sensitive data to the server that is the target of the second HTTP request.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

cURL: 7.1 - 7.75.0

CPE2.3 External links

http://curl.haxx.se/docs/CVE-2021-22876.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Man-in-the-Middle (MitM) attack

EUVDB-ID: #VU51822

Risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-22890

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to an error when handling TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. The reason for this confusion is the modified sequence from TLS 1.2 when the session ids would provided only during the TLS handshake, while in TLS 1.3 it happens post hand-shake and the code was not updated to take that changed behavior into account.

When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed.

This flaw can allow a malicious HTTPS proxy to MITM the traffic. Such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

cURL: 7.63.0 - 7.75.0

CPE2.3 External links

http://curl.haxx.se/docs/CVE-2021-22890.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



###SIDEBAR###