Qlik Sense: vulnerability flaw under attack

What is affected

Qlik Sense is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

Qlik Sense contains an HTTP tunneling vulnerability that allows an attacker to escalate privileges and execute HTTP requests on the backend server hosting the software.

What an attacker can do

This is a vulnerability flaw. It lets an attacker misuse the product in a way its maker did not intend. CISA lists it because attackers are confirmed to be using it against real systems.

How it is reached

Over the internet or network

Access the attacker needs

A basic user account

Does the victim have to do something?

No, works without the victim doing anything

CISA records this vulnerability as known to be used in ransomware campaigns: attackers use it to get in, then encrypt files and demand payment.

What to do

1. At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
2. If you administer Qlik Sense at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
3. If the product is past its support date and no fix exists, take it off the internet or retire it.

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• community.qlik.comcommunity.qlik.com/t5/Official-Support-Articles/Critical-Security-fixes-for-Qlik-Sense-Ent

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on January 13, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by February 3, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 47% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99% of all scored vulnerabilities.

Its CVSS severity score is 9.9 out of 10 (critical), as recorded in the US National Vulnerability Database.

Technical description

Qlik Sense Enterprise for Windows before August 2023 Patch 2 allows unauthenticated remote code execution, aka QB-21683. Due to improper validation of HTTP headers, a remote attacker is able to elevate their privilege by tunneling HTTP requests, allowing them to execute HTTP requests on the backend server that hosts the repository application. The fixed versions are August 2023 Patch 2, May 2023 Patch 6, February 2023 Patch 10, November 2022 Patch 12, August 2022 Patch 14, May 2022 Patch 16, February 2022 Patch 15, and November 2021 Patch 17. NOTE: this issue exists because of an incomplete fix for CVE-2023-41265.