Cinterion IoT Cellular Modules Vulnerable to SMS Compromise

Cinterion cellular modems, which are widely deployed in equipment used across industrial, healthcare and other operational technology environments, can be compromised via malicious SMS messages, researchers warn.

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Multiple modems built by Internet of Things device manufacturer Telit Cinterion have a vulnerability “that could allow a remote unauthenticated attacker to execute arbitrary code on the targeted system by sending a specially crafted SMS message,” said the U.S. National Vulnerability Database.

“This flaw enables remote attackers to execute arbitrary code via SMS, granting them unprecedented access to the modem’s operating system,” according to a vulnerability alert issued in November 2023 by Moscow-based cybersecurity firm Kaspersky. “This access also facilitates the manipulation of RAM and flash memory, increasing the potential to seize complete control over the modem’s functionalities – all without authentication or requiring physical access to the device.”

NVD rated the vulnerability 9.8 on the 10-point CVSS severity scale, because a remote attacker can use it to execute arbitrary code on a vulnerable device, potentially taking full control of the equipment and then pivoting to OT and IT networks.

Kaspersky said it first directly reported seven zero-day flaws it discovered to Telit Cinterion in February 2023, including CVE-2023-47610, which it described as being “a heap overflow vulnerability within the modem’s SUPL message handlers,” referring to a modem’s location services.

To mitigate that flaw, Kaspersky recommends users of any devices with these modems disable SMS messaging capabilities whenever possible, as well as safeguard the devices by using private access point names, or APNs, “with carefully configured security settings to limit impact of any potential exploit.”

Kaspersky said the six other zero-day vulnerabilities – designated CVE-2023-47611 through CVE-2023-47616 – trace to how the devices handle “midlets,” or MIDlets, which are Java-based applications designed to run on mobile devices. “Attackers could compromise the integrity of these applications by circumventing digital signature checks, enabling unauthorized code execution with elevated privileges,” Kaspersky said Friday, when it released more details on the vulnerabilities. “This flaw poses significant risks not only to data confidentiality and integrity, but it also escalates the threat to broader network security and device integrity.”

By exploiting the flaws, “it is possible to extract, substitute and bypass the digital signature of both user and manufacturer MIDlets and also elevate the execution privileges of any user MIDlet to the manufacturer level,” said Alexander Kozlov, a principal security researcher with Kaspersky’s computer emergency response team for industrial control systems, and his former colleague Sergey Anufrienko, in a summary of a presentation on the vulnerabilities they delivered Saturday at the OffensiveCon security conference in Berlin.

To mitigate those six vulnerabilities, Kaspersky recommends “enforcing rigorous digital signature verification for MIDlets, controlling physical access to devices and conducting regular security audits and updates.”

Kaspersky said the seven vulnerabilities are present in all versions of the following modules:

• Telit Cinterion BGS5;




• Telit Cinterion EHS5/6/8;




• Telit Cinterion PDS5/6/8;




• Telit Cinterion ELS61/81;




• Telit Cinterion PLS62.
  

Cinterion cellular modems get used across a number of industrial IoT environments, including in the manufacturing and healthcare as well as financial services and telecommunications sectors.

Telit Cinterion couldn’t be immediately reached for comment about the status of its patching efforts or mitigation advice.

Fixing the flaws would require the manufacturer of any specific device that includes a vulnerable Cinterion module to release a patch. Some devices, such as insulin monitors in hospitals or the programmable logic controllers and supervisory control and data acquisition systems used in industrial environments, might first need to be recertified with regulators before device manufacturers can push patches to users.

The vulnerabilities pose a supply-chain security risk, said Evgeny Goncharov, head of Kaspersky’s ICS CERT. “Since the modems are typically integrated in a matryoshka-style within other solutions, with products from one vendor stacked atop those from another, compiling a list of affected end products is challenging,” he said. “Affected vendors must undertake extensive efforts to manage risks, with mitigation often feasible only on the telecom operators’ side.”

The first Cinterion modules date from 2008, when they were developed by Cinterion Wireless Modules, a German machine-to-machine or M2M manufacturer. Digital security company Gemalto acquired Cinterion in 2010, after which French multinational Thales Group acquired Gemalto in in 2019. In 2022, privately held Telit, based in Irvine, California, acquired Thales’ cellular IoT product business in return for giving Thales a 25% stake in the new firm, named Telit Cinterion.

These aren’t the first critical vulnerabilities to be found in Cinterion modules. In 2022, IBM’s X-Force Red offensive security services group detailed a directory traversal flaw, designated CVE-2020-15858, in multiple Cinterion modules, including BGS5, that attackers could exploit to take control of the equipment (see: IBM Finds Flaw in Millions of Thales Wireless IoT Modules).