Overview
This blog post delves into the details of a critical vulnerability, CVE-2025-20704, that has been identified in Modems. This vulnerability could potentially lead to a remote escalation of privilege, putting at risk any system or device that uses the affected Modem. Due to the severity of this issue and its potential for system compromise or data leakage, understanding this vulnerability, how it can be exploited, and how to mitigate it is crucial for cybersecurity professionals, IT administrators, and anyone responsible for maintaining the secure operation of connected devices.
Vulnerability Summary
CVE ID: CVE-2025-20704
Severity: High – CVSS score of 8.8
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Modem | All versions before patch MOLY01516959
How the Exploit Works
The CVE-2025-20704 vulnerability is caused due to a missing bounds check in the Modem, which can lead to an out of bounds write. This flaw can be exploited by an attacker who controls a rogue base station to which a UE (User Equipment) has connected. Once the UE is connected to the rogue base station, the attacker can manipulate the data sent to the Modem, causing the Modem to write data outside of its allocated memory space. This could result in a remote escalation of privilege without the need for any additional execution privileges.
Conceptual Example Code
Let’s consider a hypothetical scenario where an attacker has set up a rogue base station and a UE has connected to it. The attacker could send malicious payload to the Modem that looks something like this:
POST /modem/interface HTTP/1.1
Host: rogue.base.station
Content-Type: application/octet-stream
{ "data": "malicious_data_that_causes_out_of_bounds_write" }This conceptual example is a gross simplification and actual attacks are likely to be more complex. But it illustrates the basic idea of how an attacker might exploit this vulnerability.
Mitigation Guidance
The most effective way to mitigate this vulnerability is to apply the vendor-provided patch (Patch ID: MOLY01516959). It is strongly recommended to test the patch in a controlled environment before deploying it into production systems to ensure it does not disrupt normal operations.
For those who are not able to immediately apply the patch, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. These security systems can be configured to detect and block potentially malicious traffic that attempts to exploit this vulnerability.
The discovery of CVE-2025-20704 serves as a reminder of the importance of implementing a rigorous cybersecurity strategy that includes regular patching and updates, as well as proactive monitoring for unusual network activity.
