Security Bulletin: Vulnerabilities in Curl affect PowerSC (CVE-2019-5435, CVE-2019-5436)

Summary

There are vulnerabilities in Curl that affect PowerSC.

Vulnerability Details

CVEID:CVE-2019-5435
**DESCRIPTION:**An integer overflow in curl’s URL API results in a buffer overflow in libcurl 7.62.0 to and including 7.64.1.
CVSS Base score: 7.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/161429 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)

CVEID:CVE-2019-5436
**DESCRIPTION:**A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through 7.64.1.
CVSS Base score: 6.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/161431 for the current score.
CVSS Vector: (CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)

Affected Products and Versions

The following fileset levels are vulnerable:

Note: To find out whether the affected PowerSC filesets are installed on your systems, refer to the lslpp command found in AIX user’s guide.

Example: rpm -qa | grep curl

Remediation/Fixes

A. FIXES

Fixes are available.

The fixes can be downloaded via ftp or http from:

<ftp://aix.software.ibm.com/aix/efixes/powersc/security/curl_fix.tar&gt;
<http://aix.software.ibm.com/aix/efixes/powersc/security/curl_fix.tar&gt;
<https://aix.software.ibm.com/aix/efixes/powersc/security/curl_fix.tar&gt;

The link above is a tar file containing this signed advisory, open source fix packages, and OpenSSL signatures for each package.

To extract the fixes from the tar file:

tar xvf curl_fix.tar

cd curl_fix

Verify you have retrieved the fixes intact:

The checksums below were generated using the “openssl dgst -sha256 [filename]” command as the following:

openssl dgst -sha256 filename KEY
-----------------------------------------------------------------------------------------------------------------------
56e394405836f1bdf7d188cef30adf5f6151fe594b39576dfbd953435e192569 ca-certificates-2016.10.7-2.aix6.1.ppc.rpm key_w_csum
5f01da544ae221c3f98ecd864782597b326f7838bb759cbb44b8366cad2eaeee curl-7.65.1-1.aix6.1.ppc.rpm key_w_csum
3ef01f3aea3e62ce402158ea892dfdb101d2c2f1c06256c6a245dc3126610bc0 db-6.2.32-2.aix6.1.ppc.rpm key_w_csum
7d1b39e1b8ab29a33edf9bb8fb589e071a6e0e06b69182f8a08776f497715f49 krb5-libs-1.16.1-2.aix6.1.ppc.rpm key_w_csum
dfd52c9b162b075abdaea908910ade3ee13d923e36a7e45cf6e1308ef5e62b52 libgcc-8.1.0-2.aix7.2.ppc.rpm key_w_csum

These sums should match exactly. The OpenSSL signatures in the tar file and on this advisory can also be used to verify the integrity of the fixes. If the sums or signatures cannot be confirmed, contact IBM Support.

openssl dgst -sha1 -verify <pubkey_file> -signature <advisory_file>.sig <advisory_file>

openssl dgst -sha1 -verify <pubkey_file> -signature <ifix_file>.sig <ifix_file>

Published advisory OpenSSL signature file location:

<http://aix.software.ibm.com/aix/efixes/powersc/security/curl_advisory.asc.sig&gt;
<https://aix.software.ibm.com/aix/efixes/powersc/security/curl_advisory.asc.sig&gt;
ftp://aix.software.ibm.com/aix/efixes/powersc/security/curl_advisory.as…

B. FIX AND INTERIM FIX INSTALLATION

IMPORTANT: If possible, it is recommended that a mksysb backup of the system be created. Verify it is both bootable and readable before proceeding.

To extract the fixes from the tar file:

tar xvf curl_fix.tar
cd curl_fix

To install a fix package:

rpm -ivh *.rpm
rpm -Uvh *.rpm

Interim fixes have had limited functional and regression testing but not the full regression testing that takes place for Service Packs; however, IBM does fully support them.

Workarounds and Mitigations

None.