CVE-2024-11064 Overview
CVE-2024-11064 is an OS Command Injection vulnerability [CWE-78] affecting the D-Link DSL6740C modem. The flaw resides in a specific functionality exposed through the device's SSH and Telnet management interfaces. Authenticated remote attackers with administrator privileges can inject and execute arbitrary system commands on the underlying operating system.
The vulnerability carries a CVSS 3.1 score of 7.2 (HIGH) and is exploitable over the network with low attack complexity. Successful exploitation compromises the confidentiality, integrity, and availability of the affected device.
Critical Impact
Attackers holding administrator credentials can execute arbitrary OS commands on the modem, enabling full device takeover, traffic interception, and use of the router as a pivot into internal networks.
Affected Products
- D-Link DSL6740C modem
- D-Link DSL6740C firmware (all versions prior to the vendor-supplied fix)
- Deployments exposing SSH or Telnet management interfaces
Discovery Timeline
- 2024-11-11 - CVE-2024-11064 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-11064
Vulnerability Analysis
The DSL6740C exposes administrative functionality through SSH and Telnet services. One or more command handlers within this administrative surface pass user-controlled input into an OS command execution context without adequate sanitization or argument separation. This behavior aligns with CWE-78, Improper Neutralization of Special Elements used in an OS Command.
An authenticated administrator can inject shell metacharacters (such as ;, |, &&, or backticks) into the vulnerable parameter. The injected payload executes with the privileges of the service handling the command, which on consumer modem firmware is typically the root user. This grants the attacker full command execution on the embedded Linux platform.
Because the attack vector is Network and privileges required are High, exploitation depends on the attacker first obtaining administrator credentials. Default credentials, credential reuse, brute-forcing of weak passwords, or a preceding authentication bypass would make this vulnerability practically exploitable at scale.
Root Cause
The root cause is the direct concatenation of attacker-supplied input into an OS command string without input validation, allowlisting, or safe API usage (such as execve with argument arrays). The affected handler treats administrative input as trusted despite it originating from a remotely accessible protocol.
Attack Vector
Exploitation requires network reachability to the modem's SSH or Telnet management interface and valid administrator credentials. Once authenticated, the attacker submits a crafted command through the vulnerable functionality. The embedded shell executes both the intended command and the appended attacker payload. See the TW-CERT Security Advisory for vendor-coordinated details.
No verified public proof-of-concept code is available. The vulnerability mechanism is command metacharacter injection into an administrative command handler exposed via SSH and Telnet.
Detection Methods for CVE-2024-11064
Indicators of Compromise
- Unexpected SSH or Telnet sessions to the DSL6740C management interface from external or unmanaged internal addresses.
- Administrative command inputs containing shell metacharacters such as ;, |, &&, $( ), or backticks.
- Outbound connections initiated by the modem to attacker-controlled infrastructure, including unusual DNS lookups or TFTP/HTTP downloads of secondary payloads.
- Unexpected changes to modem configuration, DNS server settings, firewall rules, or routing tables.
Detection Strategies
- Monitor authentication logs for administrator logins to the modem from unusual sources or at unusual times.
- Inspect available management-plane logs for command strings containing shell metacharacters submitted to administrative endpoints.
- Alert on new listening services or reverse shells originating from the modem's IP address via NetFlow or firewall logs.
Monitoring Recommendations
- Baseline normal administrative access patterns and alert on deviations in source IP, protocol, or session duration.
- Track DNS resolution changes advertised by the modem to downstream clients, which is a common post-compromise action on routers.
- Forward available syslog data from the modem into a centralized log platform for correlation with broader network telemetry.
How to Mitigate CVE-2024-11064
Immediate Actions Required
- Restrict SSH and Telnet access on the DSL6740C to trusted management networks only; block these services on the WAN interface.
- Rotate the modem administrator password to a strong, unique credential and disable any default accounts.
- Disable Telnet entirely where possible, as it transmits credentials in cleartext and expands the exposure of this vulnerability.
- Audit administrator account inventory and remove unused accounts.
Patch Information
Refer to the TW-CERT Security Bulletin and the vendor advisory for the corrected firmware version and update instructions. Apply the D-Link firmware update for the DSL6740C as soon as it is available for your regional SKU.
Workarounds
- Place the modem's management interfaces behind an out-of-band management VLAN or ACL that permits only administrative workstations.
- Enforce multi-factor or certificate-based access to any jump host used to reach the modem, reducing the likelihood of credential compromise.
- Disable remote (WAN-side) administration and require on-LAN access for configuration changes.
- Monitor the device for anomalous outbound traffic that could indicate post-exploitation command-and-control activity.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
