Anish Mohammed - Academia.edu (original) (raw)

Papers by Anish Mohammed

This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a l... more This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a large corporate network. Several security issues arise from mismatches between the different identifier spaces used by applications, by the IPsec security policy database, and by the security infrastructure (X.509 certificates or Kerberos). Mobile hosts encounter additional problems because private IP addresses are not globally unique, and because they rely on an untrusted DNS server at the visited network. We also discuss a feature interaction in an enhanced IPsec firewall mechanism. The potential solutions are to relax the transparency of IPsec protection, to put applications directly in charge of their security and, in the long term, to redesign the security protocols not to use IP addresses as host identifiers.

Mobile computer users often have a false sense of anonymity when they connect to the Internet at ... more Mobile computer users often have a false sense of anonymity when they connect to the Internet at cafes, hotels, airports or other public places. In this paper, we analyze information leaked by mobile computers to the local access link when they are outside their home domain. While most application data can be encrypted, there is no similar protection for signaling messages in the lower layers of the protocol stack. We found that all layers of the protocol stack leak various plaintext identifiers of the user, the computer and their affiliations to the local link, which a casual attacker can observe. This violates the user's sense of privacy and may make the user or computer vulnerable to further attacks. It is, however, not possible to disable the offending protocols because many of them are critical to the mobile user experience. We argue that the most promising solutions to the information leaks are to filter outbound data, in particular name resolution requests, and to disable unnecessary service discovery depending on the network location. This is because most information leaks result from failed attempts by roaming computers to connect to services that are not available in the current access network.

This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a l... more This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a large corporate network. Several security issues arise from mismatches between the different identifier spaces used by applications, by the IPsec security policy database, and by the security infrastructure (X.509 certificates or Kerberos). Mobile hosts encounter additional problems because private IP addresses are not globally unique, and because they rely on an untrusted DNS server at the visited network. We also discuss a feature interaction in an enhanced IPsec firewall mechanism. The potential solutions are to relax the transparency of IPsec protection, to put applications directly in charge of their security and, in the long term, to redesign the security protocols not to use IP addresses as host identifiers.

On-line gaming has seen something of a popular explosion in recent years, and is rapidly becoming... more On-line gaming has seen something of a popular explosion in recent years, and is rapidly becoming the predominant focus of many gaming platforms. Unfortunately, honesty is not a virtue favoured by all players in these networks. This paper proposes a Trusted Computing based security framework for gaming consoles that will be resilient to platform modification based cheating mechanisms. In addition to this, we propose a Trusted Computing based auction mechanism that can be used for auctioning in-game items.

This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a l... more This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a large corporate network. Several security issues arise from mismatches between the different identifier spaces used by applications, by the IPsec security policy database, and by the security infrastructure (X.509 certificates or Kerberos). Mobile hosts encounter additional problems because private IP addresses are not globally unique, and because they rely on an untrusted DNS server at the visited network. We also discuss a feature interaction in an enhanced IPsec firewall mechanism. The potential solutions are to relax the transparency of IPsec protection, to put applications directly in charge of their security and, in the long term, to redesign the security protocols not to use IP addresses as host identifiers.

Mobile computer users often have a false sense of anonymity when they connect to the Internet at ... more Mobile computer users often have a false sense of anonymity when they connect to the Internet at cafes, hotels, airports or other public places. In this paper, we analyze information leaked by mobile computers to the local access link when they are outside their home domain. While most application data can be encrypted, there is no similar protection for signaling messages in the lower layers of the protocol stack. We found that all layers of the protocol stack leak various plaintext identifiers of the user, the computer and their affiliations to the local link, which a casual attacker can observe. This violates the user's sense of privacy and may make the user or computer vulnerable to further attacks. It is, however, not possible to disable the offending protocols because many of them are critical to the mobile user experience. We argue that the most promising solutions to the information leaks are to filter outbound data, in particular name resolution requests, and to disable unnecessary service discovery depending on the network location. This is because most information leaks result from failed attempts by roaming computers to connect to services that are not available in the current access network.

This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a l... more This paper recounts some lessons that we learned from the deployment of host-to-host IPsec in a large corporate network. Several security issues arise from mismatches between the different identifier spaces used by applications, by the IPsec security policy database, and by the security infrastructure (X.509 certificates or Kerberos). Mobile hosts encounter additional problems because private IP addresses are not globally unique, and because they rely on an untrusted DNS server at the visited network. We also discuss a feature interaction in an enhanced IPsec firewall mechanism. The potential solutions are to relax the transparency of IPsec protection, to put applications directly in charge of their security and, in the long term, to redesign the security protocols not to use IP addresses as host identifiers.

On-line gaming has seen something of a popular explosion in recent years, and is rapidly becoming... more On-line gaming has seen something of a popular explosion in recent years, and is rapidly becoming the predominant focus of many gaming platforms. Unfortunately, honesty is not a virtue favoured by all players in these networks. This paper proposes a Trusted Computing based security framework for gaming consoles that will be resilient to platform modification based cheating mechanisms. In addition to this, we propose a Trusted Computing based auction mechanism that can be used for auctioning in-game items.