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Perl: bypassing Safe.pm via overloading
Synthesis of the vulnerability
An attacker can define methods or overload operators, in order to bypass restrictions imposed by the Safe.pm module of Perl.
Impacted products: Fedora, Mandriva Corporate, MES, Mandriva Linux, Mandriva NF, openSUSE, Solaris, Perl Module ~ not comprehensive, RHEL, SLES, ESX.
Creation date: 21/05/2010.
Identifiers: 576508, BID-40302, CERTA-2010-AVI-580, CVE-2010-1168, CVE-2010-1974-REJECT, FEDORA-2010-11323, FEDORA-2010-11340, MDVSA-2010:115, openSUSE-SU-2010:0518-1, openSUSE-SU-2010:0519-1, RHSA-2010:0457-01, RHSA-2010:0458-02, SUSE-SR:2010:016, VIGILANCE-VUL-9657, VMSA-2010-0013, VMSA-2010-0013.1, VMSA-2010-0013.2, VMSA-2010-0013.3.
Description of the vulnerability
The Safe.pm module creates an environment restricting Perl features:
- Safe::reval("here a Perl code") : the Perl code is restricted
- Safe::rdo("file") : the Perl code located inside the file is restricted
However, a malicious Perl code can:
- define a destructor (DESTROY)
- define an AUTOLOAD
- overload an operator
The code located in these elements is not filtered.
An attacker can therefore define methods or overload operators, in order to bypass restrictions imposed by the Safe.pm module of Perl.
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