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Backdoor found in Linksys, Netgear Routers

552 pointsby nilsjuenemannover 11 years ago

29 comments

maxk42over 11 years ago
About a year ago I left a cable modem and internet service (Time Warner) at an apartment I was moving out of while my friend continued to stay there. I had configured the thing in a manner I thought to be fairly secure -- strong password, no broadcast, etc.. One day the internet goes down and my friend doesn&#x27;t know what to do. She calls the ISP and asks them what&#x27;s wrong. They say they can&#x27;t release any information about the service to her without my permission, so I suddenly get a three-way call explaining that my friend and the ISP representative are on the line and I need to give my authorization to access the account information. Being the person I am, I attempt to troubleshoot things over the phone before giving out any sort of account credentials. Eventually, I ask her to log into the router configuration page. She doesn&#x27;t know the password and the first one I gave her doesn&#x27;t work. The representative chimes in &quot;That&#x27;s fine -- I can just change it from here.&quot;<p>&quot;...What?&quot;<p>I was furious. Time Warner had left a backdoor in all their modems that gives them administrative access to my private connection. And yes -- she did alter the password remotely. She didn&#x27;t seem to think there was anything wrong with this. I tried googling for relevant information, but wasn&#x27;t able to find anything more than speculation at the time.
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earlzover 11 years ago
Interesting. Reminds me of the hack I did on a (mandatory) modem&#x2F;router forced on AT&amp;T users. They had a bunch of problems with it, so one day I got fed up after the millionth disconnect and cracked it open. Got a serial root shell by using the &quot;magic !&quot; command (completely randomly discovered) and dumped the source to the web UI(in Lua&#x2F;haserl). From there found the equivalent of a SQL injection vulnerability and used it to gain a remote root exploit.<p>Most annoyingly, AT&amp;T put out a firmware update some months later that closed the exploit, but didn&#x27;t fix any other problems. So, I found another more intrusive&#x2F;permanent exploit. Still waiting on them to patch it next heh. But now they are actually putting out some updates that actually fix problems too at least. Hopefully user uproar will continue to drive them to fix more problems
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X4over 11 years ago
I hacked my Fritz!Box (yeah, a bad name for a german router) and I&#x27;m entirely sure that it has a backdoor integrated too. That&#x27;s why I wiped and flashed it with an alternative image. That and the Telecom&#x27;s Speedport router are the most popular routers by far in Germany. And both have backdoors, I know that other router manufacturers also integrate backdoors from a source who works at such a company. A friend can also verify the fact, because a different employee told him the same. Also it&#x27;s public that the ISP can upgrade, modify, flash and disable features remotely. My friend&#x27;s router has wifi, but their provider disabled it remotely within the firmware (it even has an antenna) and his ISP wants him to pay 5€&#x2F;m to re-enable wifi.<p>I really wonder why nobody complained about that earlier. Also the interesting thing here is that for a very long time, you weren&#x27;t allowed to use a different router than the one provided by your ISP. Which enforced their surveillance monopoly.<p>Here&#x27;s an article about reverse engineering the backdoor in D-Link routers using IDA:<p><a href="http://www.devttys0.com/2013/10/reverse-engineering-a-d-link-backdoor/" rel="nofollow">http:&#x2F;&#x2F;www.devttys0.com&#x2F;2013&#x2F;10&#x2F;reverse-engineering-a-d-link...</a><p>PoC Available: <a href="http://pastebin.com/vbiG42VD" rel="nofollow">http:&#x2F;&#x2F;pastebin.com&#x2F;vbiG42VD</a>
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nlvdover 11 years ago
&quot;And the Chinese have probably known about this back door since 2008.&quot; <a href="http://www.microsofttranslator.com/bv.aspx?from=&amp;to=en&amp;a=http%3A%2F%2Fhi.baidu.com%2Fcygnusnow%2Fitem%2F3fd853ade9f08f9e151073a1" rel="nofollow">http:&#x2F;&#x2F;www.microsofttranslator.com&#x2F;bv.aspx?from=&amp;to=en&amp;a=htt...</a><p>That&#x27;s a pretty scary prospect. If its been &#x27;known&#x27; and exploited since at least 2008. Poor form Netgear&#x2F;Linksys.
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midas007over 11 years ago
This is not surprising. It&#x27;s a calculated risk to make a product just good enough. Development resources invested in retail wireless gear is minimal. I&#x27;ve worked on firmware for high-confidence industrial wireless gear used in mines. Most of them fall over under load, run obsolete+unpatched code and&#x2F;or reboot randomly. Retail customers will tend to just put up with it and not return the product before the merchant&#x27;s return grace period.<p>It&#x27;s a totally different attitude when the intended market is enterprise: it&#x27;s assumed that if a product causes a failure, the vendor is going to receive escalating, unpleasant phone calls until it&#x27;s resolved.
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salientover 11 years ago
Can this be fixed by changing the firmware to OpenWRT or DD-WRT?
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redx00over 11 years ago
Has anyone ever tried submitting a GPL request to <a href="http://support.linksys.com/en-us/gplcodecenter" rel="nofollow">http:&#x2F;&#x2F;support.linksys.com&#x2F;en-us&#x2F;gplcodecenter</a><p>I wonder if there is anyone still working in the GPL compliance department.
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elwellover 11 years ago
TIL: Some people know a lot more than me about hacking. That PDF was interesting, but I only understood a small fraction of it.
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dbboltonover 11 years ago
Has there been a technical write-up on this yet? I honestly tried to read the presentation and had to quit after the third superfluous meme slide.
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comic404over 11 years ago
More information: <a href="https://github.com/elvanderb/TCP-32764/blob/master/backdoor_description.pptx" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;elvanderb&#x2F;TCP-32764&#x2F;blob&#x2F;master&#x2F;backdoor_...</a><p>&quot;Mr. Guessing 2010&quot; doesn&#x27;t know shit about backdoor (superuser.com).
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nwhover 11 years ago
I have confirmed this (or something similar) is present in the Netgear DG834N as well.
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m86over 11 years ago
ScMM = SerComm, perhaps?<p>Many of Linksys&#x27; old DSL modems were manufactured by them, AFAIK.. and it seems many of the noted &#x27;probably affected&#x27; models have a SerComm manuf&#x27;ed device for at least one revision of that model line<p>More probable SerComm manuf&#x27;ed devices are visible at the WD query link below..<p><a href="http://wikidevi.com/w/index.php?title=Special%3AAsk&amp;q=[[Manuf%3A%3ASerComm]]+[[Global+type%3A%3A~embedded*]]&amp;po=%3FFCC+ID%0D%0A%3FFCC+approval+date%3DFCC+date%0D%0A%3FEstimated+date+of+release%3DEst.+release+date%0D%0A%3FEmbedded+system+type%0D%0A%3FCPU1+brand%0D%0A%3FCPU1+model%3DCPU1+mdl.%0D%0A&amp;eq=yes&amp;p[format]=broadtable&amp;sort_num=&amp;order_num=ASC&amp;p[limit]=500&amp;p[offset]=&amp;p[link]=all&amp;p[sort]=&amp;p[headers]=show&amp;p[mainlabel]=&amp;p[intro]=&amp;p[outro]=&amp;p[searchlabel]=%E2%80%A6+further+results&amp;p[default]=&amp;p[class]=sortable+wikitable+smwtable&amp;eq=yes" rel="nofollow">http:&#x2F;&#x2F;wikidevi.com&#x2F;w&#x2F;index.php?title=Special%3AAsk&amp;q=[[Manu...</a>
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dobbsbobover 11 years ago
Buy a $200 soekris box and install openbsd or m0n0wall on it, or on any old pc you have lying around with 2 network cards.
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atmosxover 11 years ago
I live in Czech Republic and my Zyxel from O2 has port 7547 open (Allegro RomPager 4.07) and you can&#x27;t do anything about it. There is no editor on the installed linux version (cropped down linux, probably openWRT or something similar), no package manager no nothing.<p>If I flash the firmware warranty is void and I have no user&#x2F;pass to re-enable the ADSL. So basically, my router is a <i>hostile</i> AP.<p>Given the fact that, it&#x27;s a common pattern among ISPs in order to offer quick service - I firmly believe that ISPs do it for practical reasons - and end up killing your security, the best thing is to put the router in bridged mode and get a cheap custom-made router like carambola2[1] and install FreeBSD[2] on it.<p>Disclosure: I donated one of these devices to Adrian Chadd[3] in order for him to port FreeBSD on this device, which enabled me to use PF[4] - my favorite firewall - but I have no affiliation otherwise with 8devices or FreeBSD.<p>[1] <a href="http://8devices.com/carambola-2" rel="nofollow">http:&#x2F;&#x2F;8devices.com&#x2F;carambola-2</a><p>[2] <a href="https://wiki.freebsd.org/FreeBSD/mips/Carambola2" rel="nofollow">https:&#x2F;&#x2F;wiki.freebsd.org&#x2F;FreeBSD&#x2F;mips&#x2F;Carambola2</a><p>[3] <a href="https://wiki.freebsd.org/AdrianChadd" rel="nofollow">https:&#x2F;&#x2F;wiki.freebsd.org&#x2F;AdrianChadd</a><p>[4] <a href="http://pf4freebsd.love2party.net" rel="nofollow">http:&#x2F;&#x2F;pf4freebsd.love2party.net</a>
chensterover 11 years ago
Why backdoor?? That&#x27;s what I want to know.
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DROP_TABLEover 11 years ago
Am I the only one who gets really annoyed by the memes in the exploit description?
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jacob019over 11 years ago
is this backdoor only served up on the wlan or is it also exposed to the internet?
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billpgover 11 years ago
I&#x27;ve used GRC&#x27;s &quot;Shields Up&quot; and asked for a user-specified probe for port 32764 and it came back &quot;Stealth&quot;.<p>Assuming GRC isn&#x27;t out to decive me, can I assume that my router is fine?<p>Bill, using a Netgear router.
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eggshellover 11 years ago
If you want more fun with the saved nvram config files, check out <a href="http://www.nirsoft.net/utils/router_password_recovery.html" rel="nofollow">http:&#x2F;&#x2F;www.nirsoft.net&#x2F;utils&#x2F;router_password_recovery.html</a><p>He&#x27;s figured out many of their &quot;encryption&quot; methods. I&#x27;ve independently &quot;cracked&quot; most of the major ones as well, (including checksums&#x2F;headers required to write back to the router).<p>They&#x27;re all pretty broken. PRNG key streams, simple bit swaps, XOR, encryption against a static key, etc.<p>Fun stuff.
thrillgoreover 11 years ago
Thankfully I have an older WNDR3700 and I remain unaffected.<p>However seeing mention of (and an implementation of) Dual_ECC_DRBG in the slides immediately gives me a lot of pause regarding the security of my router. I love memes more than the next guy but this guy really went out of his way to make this confusing to understand.
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userbinatorover 11 years ago
I have a WGR614v6: it shows no response from port 32764 both from internet and local.<p>At first I thought it was this, which has been known for a long time now: <a href="http://wiki.openwrt.org/toh/netgear/telnet.console" rel="nofollow">http:&#x2F;&#x2F;wiki.openwrt.org&#x2F;toh&#x2F;netgear&#x2F;telnet.console</a>
spditnerover 11 years ago
Netgear routers come with a well published back door (<a href="http://wiki.openwrt.org/toh/netgear/telnet.console" rel="nofollow">http:&#x2F;&#x2F;wiki.openwrt.org&#x2F;toh&#x2F;netgear&#x2F;telnet.console</a>) that gives you telnet access from the LAN.
toxikover 11 years ago
While interesting, I wouldn&#x27;t say this is news. It has been known for quite a while.
jason_slackover 11 years ago
Does anyone have a recommendation for nice, configurable, reliable wireless router now a days? My Linksys E2000 is on the fritz and didn&#x27;t last near as long as my old WRT54G.
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undowareover 11 years ago
Don&#x27;t worry, no one will ever find out.
sly010over 11 years ago
Isn&#x27;t this necessary to roll out IPV6 anyway?
rikacometover 11 years ago
From the sounds of it, these are purposely made backdoors? or something ignored ?<p>My expression: <a href="http://i.imgur.com/pYJMKC6.jpg" rel="nofollow">http:&#x2F;&#x2F;i.imgur.com&#x2F;pYJMKC6.jpg</a>
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ballardover 11 years ago
Great discovery. Surprised no tinfoil had been mentioned about being a possible NSA &quot;diode.&quot;
henghengover 11 years ago
More information here:<p><a href="http://superuser.com/questions/166627/netgear-router-listening-on-port-32764" rel="nofollow">http:&#x2F;&#x2F;superuser.com&#x2F;questions&#x2F;166627&#x2F;netgear-router-listeni...</a>
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