FreeBSD : ruby -- $SAFE escaping vulnerability about Exception#to_s/NameError#to_s (2a093853-2495-11e2-b0c7-000d601460a4)

medium Nessus Plugin ID 62791

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Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The official ruby site reports :

Vulnerabilities found for Exception#to_s, NameError#to_s, and name_err_mesg_to_s() which is Ruby interpreter-internal API. A malicious user code can bypass $SAFE check by utilizing one of those security holes.

Ruby's $SAFE mechanism enables untrusted user codes to run in $SAFE >= 4 mode. This is a kind of sandboxing so some operations are restricted in that mode to protect other data outside the sandbox.

The problem found was around this mechanism. Exception#to_s, NameError#to_s, and name_err_mesg_to_s() interpreter-internal API was not correctly handling the $SAFE bits so a String object which is not tainted can destructively be marked as tainted using them. By using this an untrusted code in a sandbox can modify a formerly-untainted string destructively.

Ruby 1.8 once had a similar security issue. It fixed Exception#to_s and NameError#to_s, but name_err_mesg_to_str() issue survived previous security fix

Solution

Update the affected packages.

Plugin Details

Severity: Medium

ID: 62791

File Name: freebsd_pkg_2a093853249511e2b0c7000d601460a4.nasl

Version: 1.8

Type: local

Family: FreeBSD Local Security Checks

Published: 11/2/2012

Updated: 1/6/2021

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.7

CVSS v2

Risk Factor: Medium

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:ruby, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Patch Publication Date: 11/1/2012

Vulnerability Publication Date: 8/21/2012

Reference Information

CVE: CVE-2012-4464, CVE-2012-4466

Detections

Analytics