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Local privilege escalation in QRadar due to run-result-reader.sh
insecure file permissions
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Yorick Koster, September 2019

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Abstract
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It was found that the nobody user is owner of the run-result-reader.sh
script. This script is executed by the root user's crontab. Due to this
it is possible for any process running as nobody to add commands to this
script that will be executed with root privileges. In combination with a
code execution vulnerability in QRadar's web application, this can be
used for attacker's to gain full control of the QRadar system.

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See also
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CVE-2020-4270 [2]
6189657 [3] - IBM QRadar SIEM is vulnerable to privilege escalation
(CVE-2020-4270)

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Tested versions
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This issue was successfully verified on QRadar Community Edition [4]
version 7.3.1.6 (7.3.1 Build 20180723171558).

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Fix
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IBM has released the following versions of QRader in which this issue
has been resolved:

- QRadar / QRM / QVM / QNI 7.4.0 GA [5] (SFS)
- QRadar / QRM / QVM / QRIF / QNI 7.3.3 Patch 3 [6] (SFS)
- QRadar / QRM / QVM / QRIF / QNI 7.3.2 Patch 7 [7] (SFS)
- QRadar Incident Forensics 7.4.0 [8] (ISO)
- QRadar Incident Forensics 7.4.0 [9] (SFS)

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Introduction
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QRadar [10] is IBM's enterprise SIEM [11] solution. A free version of
QRadar is available that is known as QRadar Community Edition [4]. This
version is limited to 50 events per second and 5,000 network flows a
minute, supports apps, but is based on a smaller footprint for
non-enterprise use.

A local privilege escalation vulnerability was found in QRadar. This
vulnerability is possible because the script located at
/opt/qvm/iem/bin/run-result-reader.sh is configured with weak file
permissions. The owner of the script is set to the nobody user, which is
a low privileged system account use by various services - including
QRadar's web application.

The script is also started by the root user's crontab. This means that
if an attacker manages to gain access to the QRadar system as the nobody
user, it would be possible to escalate privileges to root. This is for
example possible by exploiting a code execution vulnerability in
QRadar's web application.

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Details
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The crontab of the root user contains various entries to run commands on
different moments. One of these entries will run the
run-result-reader.sh script every 20 minutes:

# crontab -l
  
[...]
  
# Update the Endpoint Manager Fixlet Action Results
*/20 * * * * /opt/qvm/iem/bin/run-result-reader.sh  > /var/log/iem-cron.log 2>&1

This script is owned by the nobody user, meaning that this user fully
controls the script and thus fully controls which commands will be
executed.

# ls -la /opt/qvm/iem/bin/run-result-reader.sh
-rwxr-xr-x 1 nobody nobody 2592 Sep 12 17:40
/opt/qvm/iem/bin/run-result-reader.sh

If the (modified) script is run from root's crontab, the commands within
the script will be executed with root privileges. Due to this it is
possible for the nobody to exploit this issue to gain root privileges
and gain full control of the QRadar system.

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References
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[1] https://www.securify.nl/advisory/SFY20200405/local-privilege-escalation-in-qradar-due-to-run-result-reader_sh-insecure-file-permissions.html
[2] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-4270
[3] https://www.ibm.com/support/pages/node/6189657
[4] https://developer.ibm.com/qradar/ce/
[5] https://www.ibm.com/support/fixcentral/swg/downloadFixes?parent=IBM%20Security&product=ibm/Other+software/IBM+Security+QRadar+SIEM&release=7.4.0&platform=Linux&function=fixId&fixids=7.4.0-QRADAR-QRSIEM-20200304205308&includeRequisites=1&includeSupersedes=0&downloadMethod=http
[6] https://www.ibm.com/support/fixcentral/swg/downloadFixes?parent=IBM%20Security&product=ibm/Other+software/IBM+Security+QRadar+SIEM&release=7.3.0&platform=Linux&function=fixId&fixids=7.3.3-QRADAR-QRSIEM-20200409085709&includeRequisites=1&includeSupersedes=0&downloadMethod=http
[7] https://www.ibm.com/support/fixcentral/swg/downloadFixes?parent=IBM%20Security&product=ibm/Other+software/IBM+Security+QRadar+SIEM&release=7.3.0&platform=Linux&function=fixId&fixids=7.3.2-QRADAR-QRSIEM-20200406171249&includeRequisites=1&includeSupersedes=0&downloadMethod=http
[8] https://www.ibm.com/support/fixcentral/swg/downloadFixes?parent=IBM%20Security&product=ibm/Other+software/IBM+Security+QRadar+Incident+Forensics&release=7.4.0&platform=Linux&function=fixId&fixids=7.4.0-QRADAR-QIFFULL-2019.18.0.20200304205308&includeRequisites=1&includeSupersedes=0&downloadMethod=http
[9] https://www.ibm.com/support/fixcentral/swg/downloadFixes?parent=IBM%20Security&product=ibm/Other+software/IBM+Security+QRadar+Incident+Forensics&release=7.4.0&platform=Linux&function=fixId&fixids=7.4.0-QRADAR-QIFSFS-2019.18.0.20200304205308&includeRequisites=1&includeSupersedes=0&downloadMethod=http
[10] https://www.ibm.com/security/security-intelligence/qradar
[11] https://en.wikipedia.org/wiki/Security_information_and_event_management