perl -- denial of service via algorithmic complexity attack on hashing routines

ID 68C1F75B-8824-11E2-9996-C48508086173
Type freebsd
Reporter FreeBSD
Modified 2016-08-22T00:00:00


Perl developers report:

In order to prevent an algorithmic complexity attack against its hashing mechanism, perl will sometimes recalculate keys and redistribute the contents of a hash. This mechanism has made perl robust against attacks that have been demonstrated against other systems. Research by Yves Orton has recently uncovered a flaw in the rehashing code which can result in pathological behavior. This flaw could be exploited to carry out a denial of service attack against code that uses arbitrary user input as hash keys. Because using user-provided strings as hash keys is a very common operation, we urge users of perl to update their perl executable as soon as possible.