SB2021101513 - Amazon Linux AMI update for httpd24
Published: October 15, 2021 Updated: December 18, 2023
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 8 secuirty vulnerabilities.
1) Inconsistent interpretation of HTTP requests (CVE-ID: CVE-2021-33193)
The vulnerability allows a remote attacker to preform HTTP/2 request smuggling attacks.
The vulnerability exists due to improper validation of HTTP/2 requests in mod_proxy in Apache HTTP Server. A remote attacker can send a specially crafted HTTP/2 request to the server and smuggle arbitrary HTTP headers.
Successful exploitation of vulnerability may allow an attacker to poison web server cache and perform phishing attacks.
2) NULL pointer dereference (CVE-ID: CVE-2021-34798)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error. A remote attacker can send a specially crafted HTTP request to the affected web server and perform a denial of service (DoS) attack.
3) Out-of-bounds read (CVE-ID: CVE-2021-36160)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a boundary condition in the mod_proxy_uwsgi module in Apache HTTP Server. A remote attacker can send an HTTP request with specially crafted uri-path, trigger an out-of-bounds read and perform a denial of service (DoS) attack.
4) Buffer overflow (CVE-ID: CVE-2021-39275)
The vulnerability allows a remote attacker to execute arbitrary code on the target system or perform a denial of service attack.
The vulnerability exists due to a boundary error within the ap_escape_quotes() function. A remote attacker can send a specially crafted request to the web server, trigger memory corruption and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system but requires that the Apache module passes untrusted data to the affected function.
According to vendor, No included modules pass untrusted data to these functions
5) Server-Side Request Forgery (SSRF) (CVE-ID: CVE-2021-40438)
The disclosed vulnerability allows a remote attacker to perform SSRF attacks.
The vulnerability exists due to insufficient validation of user-supplied input within the mod_proxy module in Apache HTTP Server. A remote attacker can send a specially crafted HTTP request with a chosen uri-path and trick the web server to initiate requests to arbitrary systems.
Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.
6) NULL pointer dereference (CVE-ID: CVE-2021-41524)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error when processing HTTP/2 requests. A remote attacker can send a specially crafted HTTP/2 request to the affected Apache HTTP server and perform a denial of service (DoS) attack.
7) Path traversal (CVE-ID: CVE-2021-41773)
The vulnerability allows a remote attacker to perform directory traversal attacks.
The vulnerability exists due to input validation error when processing directory traversal sequences. A remote attacker can send a specially crafted HTTP request to map URLs to files outside the expected document root. If files outside of the document root are not protected by "require all denied" these requests can succeed. Additionally this flaw could leak the source of interpreted files like CGI scripts.
The vulnerability can be used to execute arbitrary OS commands on the system.
Note, the vulnerability is being actively exploited in the wild.
8) OS Command Injection (CVE-ID: CVE-2021-42013)
The vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.
The vulnerability exists due to insufficient fix for the path traversal vulnerability #VU57063 (CVE-2021-41733). A remote unauthenticated attacker can send a specially crafted HTTP request to the affected server and execute arbitrary OS commands on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Remediation
Install update from vendor's website.