Square Wheels and Round Tuits Steven M. Bellovin http://www.cs.columbia.edu/~smb Columbia University April 4, 2006 1 / 22
A Conversation, Circa 1981 Me: You get a lot more performance if you A Conversation, Circa 1981 A Talk, Circa 1982 buffer disk I/O The Sins of the Fathers. . . Hobbyist: But then I can’t just eject the floppy A History Lesson Me: You also need memory protection The Root Cause Hobbyist: Why? I’m the only one using the There is a Threat Cell Phone/PDA machine Viruses More Problems Me: (Argghh!) Bellovin’s Laws of Networking Interconnections We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 2 / 22
A Talk, Circa 1982 Me: Writing code in a high-level language will A Conversation, Circa 1981 A Talk, Circa 1982 improve productivity and reduce bugs The Sins of the Fathers. . . Audience: You don’t understand how small A History Lesson these machines are! The Root Cause Me: They’ll get bigger There is a Threat Cell Phone/PDA Audience: But today they’re small Viruses More Problems Bellovin’s Laws of Networking Interconnections We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 3 / 22
The Sins of the Fathers. . . “Programs written specifically for IBM A Conversation, ■ Circa 1981 A Talk, Circa 1982 compatibles could run faster by bypassing slow The Sins of the Fathers. . . MS-DOS functions, e.g. by writing video A History Lesson information directly to the area of memory The Root Cause assigned to it.” —Wikipedia entry on DOS There is a Threat Cell Phone/PDA That meant that Windows 95 had to permit Viruses ■ More Problems such behavior, and hence couldn’t really run Bellovin’s Laws of Networking Interconnections protected We Have to Start Somewhere Windows 98 couldn’t, either; on Windows XP, ■ The Square Wheel Parts of a Solution most users run as Administrator because many Securing New Systems applications require it Principles Solution Characteristics We are paying today for decisions made 25 ■ Retrofits It May be Easier years ago 4 / 22
A History Lesson Mainframes, 1960 Single application at a time, A Conversation, Circa 1981 A Talk, Circa 1982 no memory protection, limited address space The Sins of the Fathers. . . A History Lesson The Root Cause There is a Threat Cell Phone/PDA Viruses More Problems Bellovin’s Laws of Networking Interconnections We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 5 / 22
A History Lesson Mainframes, 1960 Single application at a time, A Conversation, Circa 1981 A Talk, Circa 1982 no memory protection, limited address space The Sins of the Fathers. . . Minis, 1970 Single application at a time, no A History Lesson memory protection, limited address space The Root Cause There is a Threat Cell Phone/PDA Viruses More Problems Bellovin’s Laws of Networking Interconnections We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 5 / 22
A History Lesson Mainframes, 1960 Single application at a time, A Conversation, Circa 1981 A Talk, Circa 1982 no memory protection, limited address space The Sins of the Fathers. . . Minis, 1970 Single application at a time, no A History Lesson memory protection, limited address space The Root Cause Micros, 1980 Single application at a time, no There is a Threat Cell Phone/PDA memory protection, limited address space Viruses More Problems Bellovin’s Laws of Networking Interconnections We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 5 / 22
A History Lesson Mainframes, 1960 Single application at a time, A Conversation, Circa 1981 A Talk, Circa 1982 no memory protection, limited address space The Sins of the Fathers. . . Minis, 1970 Single application at a time, no A History Lesson memory protection, limited address space The Root Cause Micros, 1980 Single application at a time, no There is a Threat Cell Phone/PDA memory protection, limited address space Viruses More Problems PCs, 1990 Single application at a time, no Bellovin’s Laws of Networking Interconnections memory protection, limited address space We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 5 / 22
A History Lesson Mainframes, 1960 Single application at a time, A Conversation, Circa 1981 A Talk, Circa 1982 no memory protection, limited address space The Sins of the Fathers. . . Minis, 1970 Single application at a time, no A History Lesson memory protection, limited address space The Root Cause Micros, 1980 Single application at a time, no There is a Threat Cell Phone/PDA memory protection, limited address space Viruses More Problems PCs, 1990 Single application at a time, no Bellovin’s Laws of Networking Interconnections memory protection, limited address space We Have to Start Somewhere Embedded systems, now . . . The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 5 / 22
A Conversation, Circa 1981 A Talk, Circa 1982 The Sins of the Fathers. . . A History Lesson The Root Cause Those who cannot remember the past are There is a Threat Cell Phone/PDA condemned to repeat it. Viruses More Problems Bellovin’s Laws of Networking —George Santayana, 1906 Interconnections We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 6 / 22
The Root Cause Vendors shipped as soon as the hardware was A Conversation, ■ Circa 1981 A Talk, Circa 1982 capable of handling base functionality The Sins of the Fathers. . . A year later, the better hardware is used for ■ A History Lesson more functionality The Root Cause By the time people think about security, ■ There is a Threat Cell Phone/PDA there’s an installed base problem Viruses More Problems Besides, no one believed there was a problem Bellovin’s Laws of ■ Networking Interconnections We have two challenges: ■ We Have to Start Somewhere The Square Wheel To ensure that new systems are designed ◆ Parts of a Solution Securing New properly Systems Principles To figure out how to retrofit legacy ◆ Solution Characteristics systems Retrofits It May be Easier 7 / 22
A Conversation, Circa 1981 A Talk, Circa 1982 The Sins of the Fathers. . . A History Lesson The Root Cause There is a Threat Cell Phone/PDA “Software longa, hardware brevis” Viruses More Problems —Melinda Shore Bellovin’s Laws of Networking Interconnections We Have to Start Somewhere The Square Wheel Parts of a Solution Securing New Systems Principles Solution Characteristics Retrofits It May be Easier 8 / 22
There is a Threat 34 security incidents targetted at process A Conversation, ■ Circa 1981 A Talk, Circa 1982 plants were identified between 1995 and 2003 The Sins of the Fathers. . . 29% of the incidents led to companies losing ■ A History Lesson the ability to monitor or control the plant The Root Cause 36% of external attacks came through the ■ There is a Threat Cell Phone/PDA Internet Viruses More Problems The number of incidents has been increasing Bellovin’s Laws of ■ Networking Interconnections sharply since 2000. We Have to Start Somewhere The Square Wheel Source: http://www.crime-research.org/news/ Parts of a Solution Securing New 19.10.2004/727/ Systems Principles Solution Characteristics Retrofits It May be Easier 9 / 22
Cell Phone/PDA Viruses “Prepare for the likelihood of an increasing A Conversation, ■ Circa 1981 A Talk, Circa 1982 number of threats as time goes on.” The Sins of the Fathers. . . (Microsoft.com) A History Lesson “Cardtrap.A, a Trojan that attacks Symbian ■ The Root Cause mobile phone operating systems, attempts to There is a Threat Cell Phone/PDA infect users’ PCs if they insert the phone’s Viruses More Problems memory card into their computers.” Bellovin’s Laws of Networking Interconnections (news.com) We Have to Start Somewhere “What if a virus drained your cell’s battery and ■ The Square Wheel Parts of a Solution suddenly you couldn’t be reached?” . . . “Once Securing New Systems initiated, it sends the attacker an email Principles Solution Characteristics containing the IP address of your PDA.” Retrofits (Symantec.com) It May be Easier 10 / 22
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