The version of httpd24 installed on the remote host is prior to 2.4.51-1.94. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS-2021-1543 advisory.

  - A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead     to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.
    (CVE-2021-33193)

  - Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP     Server 2.4.48 and earlier. (CVE-2021-34798)

  - A carefully crafted request uri-path can cause mod_proxy_uwsgi to read above the allocated memory and     crash (DoS). This issue affects Apache HTTP Server versions 2.4.30 to 2.4.48 (inclusive). (CVE-2021-36160)

  - ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules     pass untrusted data to these functions, but third-party / external modules may. This issue affects Apache     HTTP Server 2.4.48 and earlier. (CVE-2021-39275)

  - A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the     remote user. This issue affects Apache HTTP Server 2.4.48 and earlier. (CVE-2021-40438)

  - While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request     processing, allowing an external source to DoS the server. This requires a specially crafted request. The     vulnerability was recently introduced in version 2.4.49. No exploit is known to the project.
    (CVE-2021-41524)

  - A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could     use a path traversal attack to map URLs to files outside the directories configured by Alias-like     directives. If files outside of these directories are not protected by the usual default configuration     require all denied, these requests can succeed. If CGI scripts are also enabled for these aliased     pathes, this could allow for remote code execution. This issue is known to be exploited in the wild. This     issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found     to be incomplete, see CVE-2021-42013. (CVE-2021-41773)

  - It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. An attacker     could use a path traversal attack to map URLs to files outside the directories configured by Alias-like     directives. If files outside of these directories are not protected by the usual default configuration     require all denied, these requests can succeed. If CGI scripts are also enabled for these aliased     pathes, this could allow for remote code execution. This issue only affects Apache 2.4.49 and Apache     2.4.50 and not earlier versions. (CVE-2021-42013)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Detections

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Amazon Linux AMI : httpd24 (ALAS-2021-1543)

critical Nessus Plugin ID 154188

Version 1.16