FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

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

Affected packages
perl < 5.12.4_5
5.14.0 <= perl < 5.14.2_3
5.16.0 <= perl < 5.16.2_1
perl-threaded < 5.12.4_5
5.14.0 <= perl-threaded < 5.14.2_3
5.16.0 <= perl-threaded < 5.16.2_1

Details

VuXML ID 68c1f75b-8824-11e2-9996-c48508086173
Discovery 2013-03-04
Entry 2013-03-10

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.

References

CVE Name CVE-2013-1667
URL http://www.nntp.perl.org/group/perl.perl5.porters/2013/03/msg199755.html