On August 20th, the LedgerSMB project was advised of a security
vulnerability in the code. Please see below our security advisory.
Insufficient protection against 'clickjacking'
Summary:
========
LedgerSMB does not sufficiently guard against being wrapped by
other sites, making it vulnerable to 'clickjacking. This allows
an attacker to trick a targetted user to execute unintended actions.
Known vulnerable:
=================
All of:
- 1.1.0 upto 1.1.12 (including)
- 1.2.0 upto 1.2.26 (including)
- 1.3.0 upto 1.3.47 (including)
- 1.4.0 upto 1.4.42 (including)
- 1.5.0 upto 1.5.30 (including)
- 1.6.0 upto 1.6.33 (including)
- 1.7.0 upto 1.7.32 (including)
- 1.8.0 upto 1.8.17 (including)
Known fixed:
============
- 1.7.33
- 1.8.18
Details:
========
In a clickjacking attack, an attacker (invisibly) wraps the vulnerable
site in his own site, carefully placing elements of his own site over
elements of the wrapped site, tricking the user into performing unintended
actions on the vulnerable site. More information on clickjacking is on the
OWASP page at
https://owasp.org/www-community/attacks/Clickjacking The lack of protection dates back to version 1.0, although it must
be noted that mitigation measures were first available in browsers
as of 2011 -- the year of the release of 1.3.0.
Severity:
=========
CVSSv3.1 Base Score: 5.9 (Medium)
CVSSv3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N
Recommendations:
================
We recommend all users to upgrade to known-fixed versions. Versions prior
to 1.7 are end-of-life and will not receive security fixes from the
LedgerSMB project.
Users who cannot upgrade, may apply the included patches or are advised
to contact a vendor for custom support.
As a workaround, administrators may configure their webservers to add
the Content-Security-Policy header as documented in the content
security policy site at
https://content-security-policy.com/#server.
References:
===========
CVE-2021-3731 (LedgerSMB)
https://ledgersmb.org/cve-2021-3731-clickjacking https://huntr.dev/bounties/5664331d-f5f8-4412-8566-408f8655888a/Reported by:
============
sudheendra17, user of the
huntr.dev platform
Patches:
========
Patch for LedgerSMB 1.8 (1.8.0 upto 1.8.17, including):
-------------------------------------------------------
[[[
diff --git a/lib/LedgerSMB/PSGI.pm b/lib/LedgerSMB/PSGI.pm
index b0b20a95b..a4785a9f1 100644
--- a/lib/LedgerSMB/PSGI.pm
+++ b/lib/LedgerSMB/PSGI.pm
@@ -122,6 +122,9 @@ sub old_app {
return Plack::Util::response_cb(
$handler->($env),
sub {
+ Plack::Util::header_set($_[0]->[1],
+ 'Content-Security-Policy',
+ q{frame-ancestors 'self'});
if (not Plack::Util::header_exists($_[0]->[1],
'X-LedgerSMB-App-Content')) {
Plack::Util::header_push($_[0]->[1],
@@ -179,6 +182,9 @@ sub psgi_app {
}
};
+ Plack::Util::header_set($res->[1],
+ 'Content-Security-Policy',
+ q{frame-ancestors 'self'});
return $res;
}
]]]
Patch for LedgerSMB 1.7 (1.7.0 upto 1.7.32, including):
-------------------------------------------------------
[[[
diff --git a/lib/LedgerSMB/PSGI.pm b/lib/LedgerSMB/PSGI.pm
index ec8be07f1..bcb478524 100644
--- a/lib/LedgerSMB/PSGI.pm
+++ b/lib/LedgerSMB/PSGI.pm
@@ -91,6 +91,9 @@ sub old_app {
return Plack::Util::response_cb(
$handler->(@_),
sub {
+ Plack::Util::header_set($_[0]->[1],
+ 'Content-Security-Policy',
+ q{frame-ancestors 'self'});
if (not Plack::Util::header_exists($_[0]->[1],
'X-LedgerSMB-App-Content')) {
Plack::Util::header_push($_[0]->[1],
@@ -159,6 +162,9 @@ sub psgi_app {
}
};
+ Plack::Util::header_set($res->[1],
+ 'Content-Security-Policy',
+ q{frame-ancestors 'self'});
return $res;
}
]]]
--
Bye,
Erik.
Robust and Flexible. No vendor lock-in.
