Qlik Sense: file access 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 a path traversal vulnerability that allows a remote, unauthenticated attacker to create an anonymous session by sending maliciously crafted HTTP requests. This anonymous session could allow the attacker to send further requests to unauthorized endpoints.

What an attacker can do

This is a file access flaw. It lets an attacker read or write files they should never reach, such as configuration files that hold passwords, or upload a malicious file that the system then runs.

How it is reached

Over the internet or network

Access the attacker needs

No account needed

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 remediations or mitigations per vendor instructions or discontinue use of the product if remediation or 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 December 7, 2023, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by December 28, 2023, 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 85% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99.7% of all scored vulnerabilities.

Its CVSS severity score is 6.5 out of 10 (medium), as recorded in the US National Vulnerability Database.

Technical description

A path traversal vulnerability found in Qlik Sense Enterprise for Windows for versions May 2023 Patch 3 and earlier, February 2023 Patch 7 and earlier, November 2022 Patch 10 and earlier, and August 2022 Patch 12 and earlier allows an unauthenticated remote attacker to generate an anonymous session. This allows them to transmit HTTP requests to unauthorized endpoints. This is fixed in August 2023 IR, May 2023 Patch 4, February 2023 Patch 8, November 2022 Patch 11, and August 2022 Patch 13.