The remote host is missing an update to asterisk announced via advisory DSA 2225-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202225-1

Several vulnerabilities have been discovered in Asterisk, an Open Source PBX and telephony toolkit. CVE-2011-1147 Matthew Nicholson discovered that incorrect handling of UDPTL packets may lead to denial of service of the execution of arbitrary code. CVE-2011-1174 Blake Cornell discovered that incorrect connection handling in the manager interface may lead to denial of service. CVE-2011-1175 Blake Cornell and Chris May discovered that incorrect TCP connection handling may lead to denial of service. CVE-2011-1507 Tzafrir Cohen discovered that insufficient limitation of connection requests in several TCP based services may lead to denial of service. Please see http://downloads.asterisk.org/pub/security/AST-2011-005.html for details. CVE-2011-1599 Matthew Nicholson discovered a privilege escalation vulnerability in the manager interface. For the oldstable distribution (lenny), this problem has been fixed in version 1:1.4.21.2~dfsg-3+lenny2.1. For the stable distribution (squeeze), this problem has been fixed in version 1:1.6.2.9-2+squeeze2. For the unstable distribution (sid), this problem has been fixed in version 1:1.8.3.3-1. We recommend that you upgrade your asterisk packages.