SB2021062142 - Red Hat update for JBoss Core Services Pack Apache Server
Published: June 21, 2021 Updated: October 28, 2023
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 8 secuirty vulnerabilities.
1) Information disclosure (CVE-ID: CVE-2020-8169)
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to cURL sends a DNS query with the provided credentials for HTTP authentication when processing redirects. A remote attacker that controls a DNS server can gain access to HTTP authenticated credentials.
2) Information disclosure (CVE-ID: CVE-2020-8284)
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to the way cURL handles PASV responses. A remote attacker with control over malicious FTP server can use the PASV response to trick curl into connecting
back to a given IP address and port, and this way potentially make curl
extract information about services that are otherwise private and not
disclosed, for example doing port scanning and service banner extractions.
3) Uncontrolled Recursion (CVE-ID: CVE-2020-8285)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due tu uncontrolled recursion when processing FTP responses within the wildcard matching functionality, which allows a callback (set
with <a href="https://curl.se/libcurl/c/CURLOPT_CHUNK_BGN_FUNCTION.html">CURLOPT_CHUNK_BGN_FUNCTION</a>) to return information back to libcurl on
how to handle a specific entry in a directory when libcurl iterates over a
list of all available entries. A remote attacker who controls the malicious FTP server can trick the victim to connect to it and crash the application, which is using the affected libcurl version.
4) Improper Check for Certificate Revocation (CVE-ID: CVE-2020-8286)
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to incorrectly implemented checks for OCSP stapling. A remote attacker can provide a fraudulent OCSP response that would appear fine, instead of the real one.
5) Information disclosure (CVE-ID: CVE-2021-22876)
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.
6) Man-in-the-Middle (MitM) attack (CVE-ID: CVE-2021-22890)
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.
7) Use-after-free (CVE-ID: CVE-2021-22901)
The vulnerability allows a remote attacker to crash the application or compromise the vulnerable system.
The vulnerability exists due to a use-after-free error when processing creation of new TLS sessions or during client certificate negotiation. A remote attacker can force the application to connect to a malicious server, trigger a use-after-free error and crash the application.
Remote code execution is also possible if the application can be forced to initiate multiple transfers with a reused HTTP/1.1 connection or multiplexed HTTP/2 connection in order to inject a crafted memory content into the correct place in memory.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system but requires that libcurl is using OpenSSL.
8) NULL pointer dereference (CVE-ID: CVE-2021-31618)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error in mod_http2 in Apache HTTP server. A remote attacker can send specially crafted request to the server and perform a denial of service (DoS) attack.
Remediation
Install update from vendor's website.