mailing list archives
Re: Issues in Netgear WGR614 wireless router
From: Liam <liamtr () gmail com>
Date: Sat, 15 Dec 2012 11:29:06 +1100
Is the EEPROM easily removable or does it need to be unsoldered? Any
chance you have a picture of the chip (preferably while still on the
board) so those of us who care can either remove or smash it before
turfing one of these routers out (to prevent dumpster divers potentially
recovering such data)?
On 14/12/2012 6:17 PM, gsuberland () gmail com wrote:
I've been reverse engineering the Netgear WGR614 wireless router, which has been one of the most popular devices
shipped by major ISPs in the UK over the last ten years.
After disassembling the device and identifying the components, I noticed that the firmware and all settings are stored
on a single EEPROM (flash) chip, specifically a Macronix MX25L1605 SPI 16Mbit EEPROM. Other variants of the device may
use slightly different chips, but they all seem to use SPI EEPROMs with identical I/O commands. I de-soldered the IC
and hooked it up to a BusPirate, and used it to extract the entire contents of the chip.
I quickly discovered two interesting things:
First, I found a hard-coded credential used for direct serial programming. Using it requires direct physical access and you
have to solder wires onto the board. Despite this not being particularly interesting, this issue has been assigned as
CVE-2012-6340 anyway. It's always good to have the information out there.
Second, I noticed that there were multiple copies of my config file, and all passwords (for both control panel and wifi) within
them are plain-text. It turns out that, in order to prevent config file corruption, the router re-generates the entire config
file and writes a new copy directly after the previous one. It then activates the new config, and soft-deletes the old file by
removing its entry from a list. Once you've changed the config several times (about 11 on this device), it hits the end of
the flash chip's storage and cycles back to the original address. However, it does not actually wipe the old config files.
This issue, assigned CVE-2012-6341, results in the ability to recover all previously used passwords on the device, for
both the control panel and WEP/WPA/WPA2, in plaintext. A factory reset does not fix this; it simply restores a default
config file onto the lower address. As such, an attacker who steals the device may recover the last-used passwords and
config, as well as many previous passwords and configuration data. There also seems to be some storage of DHCP client
information, but the data I have is inconclusive due to it being partially overwritten.
This has been confirmed on the WGR614v7 and WGR614v9 models, and is expected to be the case on all other revisions. It
also looks like the WGR624 model has the same design, so other models in the same series may be affected too.