(US military jargon) 1. Originally, a team whose purpose is to
penetrate security, and thus test security measures. These
people are paid professionals who do hacker-type tricks,
e.g. leave cardboard signs saying "bomb" in critical defence
installations, hand-lettered notes saying "Your codebooks have
been stolen" (they usually haven't been) inside safes, etc.
After a successful penetration, some high-ranking security
type shows up the next morning for a "security review" and
finds the sign, note, etc. and all hell breaks loose. Serious
successes of tiger teams sometimes lead to early retirement
for base commanders and security officers (see the
patchentry for an example).
2. Recently, and more generally, any official inspection team
problem.
A subset of tiger teams are professional
crackers, testing
the security of military computer installations by attempting
remote attacks via networks or supposedly "secure"
communication channels. Some of their escapades, if
declassified, would probably rank among the greatest hacks of
all times. The term has been adopted in commercial
computer-security circles in this more specific sense.