Hertz has confirmed it suffered a data breach as a result of the Cleo zero-day vulnerability in late 2024, with the car rental giant warning that customer data was stolen.
In a statement confirming the incident, the firm said customer data was “acquired by an unauthorized party that we understand exploited zero-day vulnerabilities within Cleo's platform in October 2024 and December 2024”.
“Hertz immediately began analyzing the data to determine the scope of the event and to identify individuals whose personal information may have been impacted,” the statement added.
Customer data exposed in the breach may vary, the company said, but is believed to include customer names, contact information, dates of birth, credit card details, and information pertaining to driver’s licenses.
Similarly, a limited number of customers may have had US social security numbers or government ID information stolen in the breach.
"A very small number of individuals may have had their Social Security or other government identification numbers, passport information, Medicare or Medicaid ID (associated with workers' compensation claims), or injury-related information associated with vehicle accident claims impacted by the event," the company warned.
Hertz said it is yet to observe any “misuse of personal information” linked to the breach, but is offering customers two years of identity monitoring services. The company also advised customers to remain vigilant for potential fraudulent activity.
Hertz the latest to disclose Cleo vulnerability impact
Hertz’ confirmation makes it the latest in a string of companies to have fallen victim to the Cleo breach. First disclosed last year, a vulnerability in the popular managed file transfer (MFT) service was pounced on by the Clop ransomware group.
The threat group initially claimed it had stolen data belonging to more than 60 companies as a result of the zero-day. This list has since grown, and earlier this year Western Alliance Bank confirmed it was among the growing list of victims.
Other confirmed victims include Chicago Public Schools, Champion Home Builders, and WK Kellogg.
Fresh research from ReliaQuest shows the impact of the Cleo breach will continue to grow for enterprises globally. Indeed, analysis by the security firm found the incident fueled a 23% increase in overall ransomware activity between Q4 and Q1 2025.
“Clop’s exploitation of Cleo highlights how weaknesses in systems can ripple across interconnected industries, disrupting supply chains, halting operations, and impacting countless businesses simultaneously,” the firm said in a blog post.
Rebecca Moody, head of data research at Comparitech, echoed this warning, noting that there’s likely to be “many more breach notifications from this exploit” as Clop has since added over 350 victims to its data leak site.
Dray Agha, senior manager of security operations at Huntress, said the incident underlines the “significant risks” posed by vulnerabilities in third-party platforms like Cleo.
“This highlights the importance of maintaining robust vulnerability management programs to identify and address security gaps in software promptly, especially those used for sensitive data transfer.”
Agha added the incident reflects a growing trend of cyber criminals targeting secure file transfer platforms. 2023, for example, saw a number of high-profile organizations impacted by the MOVEit data breach.
MORE FROM ITPRO
- The new ransomware groups worrying security researchers in 2025
- The ‘BlackLock’ group has become one of the most prolific operators in the cyber crime industry
- Warning issued over prolific 'Ghost' ransomware group
-
How to implement a four-day week in techIn-depth More companies are switching to a four-day week as they look to balance employee well-being with productivity
-
Intelligence sharing: The boost for businessesIn-depth Intelligence sharing with peers is essential if critical sectors are to be protected
-
Hackers breached a 158 year old company by guessing an employee password – experts say it’s a ‘pertinent reminder’ of the devastating impact of cyber crimeNews A Panorama documentary exposed hackers' techniques and talked to the teams trying to tackle them
-
The ransomware boom shows no signs of letting up – and these groups are causing the most chaosNews Thousands of ransomware cases have already been posted on the dark web this year
-
Everything we know about the Ingram Micro cyber attack so farNews A cyber attack on Ingram Micro severely disrupted operations and has been claimed by the SafePay ransomware group.
-
A prolific ransomware group says it’s shutting down and giving out free decryption keys to victims – but cyber experts warn it's not exactly a 'gesture of goodwill'
News The Hunters International ransomware group is rebranding and switching tactics
-
Swiss government data published following supply chain attack – here’s what we know about the culpritsNews Radix, a non-profit organization in the health promotion sector, supplies a number of federal offices, whose data has apparently been accessed.
-
Ransomware victims are getting better at haggling with hackersNews While nearly half of companies paid a ransom to get their data back last year, victims are taking an increasingly hard line with hackers to strike fair deals.
-
LockBit data dump reveals a treasure trove of intel on the notorious hacker groupNews An analysis of May's SQL database dump shows how much LockBit was really making
-
‘I take pleasure in thinking I can rid society of at least some of them’: A cyber vigilante is dumping information on notorious ransomware criminals – and security experts say police will be keeping close tabsNews An anonymous whistleblower has released large amounts of data allegedly linked to the ransomware gangs
