CVE-2015-3035: TP-Link Multiple Archer Devices Directory Traversal Vulnerability

CVE-2015-3035 is a directory traversal vulnerability affecting multiple TP-Link Archer devices. It allows a remote attacker to read arbitrary files on the device by supplying path traversal sequences in a request to the login path. For IT and security teams, this matters because routers and similar edge devices often hold configuration data, credentials, or network details; unauthorized file read can expose that information and aid further compromise of the local network.

Public detail is limited to the class of flaw and the high-level attack vector described by CISA. Confirm exact product models, firmware revisions, and fixed versions against the vendor advisory before acting.

How it works

The weakness is CWE-22 (Improper Limitation of a Pathname to a Restricted Directory). In this case, the device fails to properly sanitize path information supplied in the PATH_INFO portion of a request to the login endpoint. An attacker can insert “..” (dot-dot) sequences to climb out of the intended directory and request files elsewhere on the filesystem.

Because the vulnerability is reachable remotely and does not require authentication according to the CISA summary, an unauthenticated party who can reach the device’s web interface may be able to retrieve arbitrary files. The precise files that can be read, the exact request format beyond the PATH_INFO element, and any additional constraints are not detailed in the provided facts; treat those as items to verify in the vendor advisory and your own testing in a controlled environment.

Am I affected? How to find it in your systems

TP-Link Archer devices are commonly deployed as consumer and small-office/home-office wireless routers and gateways. They typically sit at the network edge, terminating WAN links and providing Wi-Fi and LAN services.

• Inventory all TP-Link Archer hardware on your network by checking asset management records, DHCP/DNS inventories, and physical or remote console access.
• Record the exact model and current firmware version from the device’s administration interface or management system.
• Compare those details against the list of affected products and fixed releases in the vendor advisory; do not assume a device is safe solely because it is “Archer” branded or because it appears up to date.
• Confirm whether the web management interface (especially any path under login/) is reachable from untrusted networks; exposure of that interface increases risk.
• Review web-server or device logs for requests containing “..” sequences or unusual PATH_INFO values directed at login-related URLs. Such patterns are classic indicators of directory-traversal probing, though absence of logs does not prove the device is unexploited.

If you lack centralized logging for these devices, enable it where the vendor supports it and retain logs long enough to support incident review.

How to remediate

The primary remediation is to apply the updates provided by the vendor, following the instructions in the official advisory. CISA’s required action is simply to apply updates per vendor instructions.

• Obtain the correct firmware image only from TP-Link’s official support channels for the specific model.
• Schedule a maintenance window, back up the current configuration if the vendor process allows it, apply the update, and verify the new firmware version afterward.
• After patching, change any credentials that may have been stored on or used by the device, and review configuration for unintended exposure of management services.
• As general hardening for this class of device, disable remote (WAN-side) administration if it is not required, restrict management access to dedicated management VLANs or jump hosts, and keep firmware current on a recurring schedule.

Confirm the exact fixed versions and any post-update verification steps in the vendor advisory; those details are not supplied in the facts available here.

If you can't patch immediately

When immediate patching is not possible, reduce exposure with compensating controls while you arrange the update.

• Segment the device so that its management interface is unreachable from the internet and from untrusted internal segments; allow access only from a tightly controlled management network.
• If a web application firewall or reverse proxy sits in front of the interface, consider virtual-patching rules that block path-traversal patterns (sequences such as “../” or encoded equivalents) in requests to login-related paths. Test rules carefully to avoid breaking legitimate access.
• Disable the affected web-management feature entirely if operational needs allow, or switch to an alternative management method the vendor supports (for example, local console or a different protocol) until the patch is applied.
• Increase monitoring: alert on any request containing traversal sequences, on unexpected file-access errors, and on configuration or firmware changes. Retain packet captures or detailed web logs if feasible.
• Ensure the device itself is not the sole security boundary for sensitive systems; assume that a compromised edge router can observe or alter traffic and plan network controls accordingly.

These measures lower risk but do not eliminate the vulnerability; treat them as temporary.

If your data may have been exposed

Actively exploited vulnerabilities on network devices can lead to broader breaches, including theft of credentials or configuration data that enable lateral movement. Known ransomware use of this specific CVE is not documented in the provided facts. If you suspect the device was reachable and unpatched during the period of exposure, treat any sensitive material that resided on it (configuration backups, stored passwords, certificates, logs) as potentially compromised: rotate credentials, revoke and re-issue certificates, and review downstream systems for unauthorized access. You can also run a free exposure scan of your email addresses against known breach data sets to check whether associated accounts appear in public breach corpora, then proceed with password changes and monitoring as appropriate.