if_indextoname()ID:
IFINDEXNAME_VPNCategory: Interfaces Status in RKNHardering 2.10.0: Active check Role in the verdict: High
This page describes the actual implementation in RKNHardering 2.10.0. It distinguishes what can be done without root, what requires root, and where a mitigation only reduces one signal without hiding the VPN as a whole.
detectIfindexnameVpn() iterates over ifindex values 1 through 127, calls if_indextoname(), and searches for the exact names tun0, tun1, utun0, wg0, ppp0, and xfrm0. The detail contains the name and index.
Reverse resolution of at least one index returns one of the fixed VPN-like names.
Even when the app cannot enumerate a directory or route dump, the kernel/libc resolves an index to a VPN-like name. This is strong evidence of incomplete hiding.
How the line affects the report: The line sets detected=true and is treated as a high-confidence local indicator.
Indices above 127 are not checked. The exact-name list is narrow. A userspace if_indextoname() hook can hide the line, but VPNHide’s regression oracle and the RTM dump test its consistency.
This line must be evaluated together with neighboring signals. A clean result from a single API does not simultaneously cover Java Binder, libc, raw netlink/syscalls, procfs/sysfs, local sockets, and server-side indicators.
The most reliable non-root approach is not to create a VPN interface on the phone being tested: move the tunnel to a router, travel router, separate gateway phone, or another network node. Per-app bypass in VpnService changes the route used by the selected app, but establish() still creates a system VPN interface, so local interface checks may continue to trigger. A local HTTP/SOCKS proxy mode without TUN can sometimes remove this specific vector, but it leaves listening ports and proxy settings and does not cover apps that ignore the proxy.
Laboratory-grade hiding usually requires a system Java layer and one native backend. With VPNHide, this means the APK plus Vector/LSPosed scoped only to System Framework, and exactly one of kmod, KPM, or Zygisk. For a check that may use a direct syscall or netlink, kmod/KPM is preferable: a userspace Zygisk hook can be bypassed and leaves traces inside the process. Review the VPNHide coverage map first, and download builds only from the official release page. VPNHide Next claims broader coverage, but also warns about possible boot loops and kernel panics; it should be tested only on a test device. Do not return a fabricated “clean” name only from if_indextoname(): a discrepancy between SIOCGIFINDEX/SIOCGIFNAME and RTM_GETLINK creates an oracle. The kernel backend must filter the data consistently.
adb shell 'for i in $(seq 1 127); do n=$(cat /sys/class/net/*/ifindex 2>/dev/null | grep -x "$i" -m1); [ -n "$n" ] && :; done'
adb shell ip -o link show
The exact API is best reproduced with a native harness using if_indextoname(); ip provides only a comparison snapshot.
After any change, force-stop both RKNHardering and the VPN client, start them again, and repeat the full scan. Zygisk, Xposed, and kernel modules usually require a reboot. Compare not only this line but also neighboring signals: a partial hook often creates inconsistencies between APIs.
The probe itself runs with ordinary app permissions and does not request root. The ADB commands below are for orientation only: adb shell runs under a different UID and may see either more or less than the app process. The decisive test is to run the check again after a force-stop.
Inconsistent index spoofing breaks bind-to-device behavior and route resolution, and may cause system-service failures.
Revert the most recent change: disable the added module or rule through its normal manager, reboot the device, and repeat the baseline scan. Do not layer another hook on top of an unknown state.
High. Verified against the [1, 127] range and the exact-name list; the kind is high confidence.
The status of a third-party solution does not automatically carry over to this device. A module developer’s claim is only the initial hypothesis; confirmation requires a reproducible RKNHardering result on the specific Android version, firmware, and kernel.
native_signs_probe.cpp — native probe implementation.VpnNativeDetectorChecker.kt — deep VPN verdict and confidence.vpnhide_regression_probe.cpp — consistency and oracle probes.NativeSignalId.kt — complete ID registry.NativeSignalCatalog.kt — category, slug, and line mapping.Related signals: vpnhide, trim-oracle, rtm-getlink-vpn, interface-enumeration.