https://bugzilla.redhat.com/show_bug.cgi?id=1961865
Bug ID: 1961865
Summary: perl-Net-CIDR-Lite: Incorrect handling of IP address
with leading zeros in IP octets
Product: Security Response
Hardware: All
OS: Linux
Status: NEW
Component: vulnerability
Keywords: Security
Severity: medium
Priority: medium
Assignee: security-response-team(a)redhat.com
Reporter: thoger(a)redhat.com
CC: paul(a)city-fan.org, perl-devel(a)lists.fedoraproject.org,
pzhukov(a)redhat.com, steve(a)silug.org
Target Milestone: ---
Classification: Other
It was discovered that the perl Net-CIDR-Lite module did not correctly handle
IP addresses with IP octets containing leading zeros. Leading zeros were
ignored, while the underlying system can treat such octets as octal numbers and
interpret them differently. For example, IP address of 010.0.0.1 was
considered by Net-CIDR-Lite to be the same address as 10.0.0.1, while system
may consider it to be IP address 8.0.0.1.
Reference:
https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distr...
This issue was fixed in Net-CIDR-Lite version 0.22 via this change:
https://metacpan.org/diff/file?target=STIGTSP/Net-CIDR-Lite-0.22/Lite.pm&...
An example of a potentially vulnerable use case can be found in the
SpamAssassin's URILocalBL plugin:
https://svn.apache.org/viewvc/spamassassin/tags/spamassassin_release_3_4_...
It allows checking URLs extracted from emails against locally defined blacklist
of IP ranges. IP addresses to check are typically obtained by resolving host
names used in URLs. However, URLs with IP addresses can be used directly.
Hence, this issue could potentially lead to a bypass of the defined blacklist.
Note that this plugin does not seem to be affected due to the use of a strict
regular expression used to determine if URL contains host name or IP address.
That regular expression does not consider addresses with leading zeros as valid
IP addresses and performs their resolution, translating the IP string to how
system interprets it.
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