Meta tags:

Headings (most frequently used words):

the, to, of, hotspots, vs, august, why, dns, requests, harder, misconceptions, and, secure, fragment, cache, doesn, mathy, vanhoef, pages, wednesday, 2024, thursday, 10, 2023, are, leaked, another, exploit, flaw, discussion, tuesday, 18, may, 2021, blog, archive, subscribe, popular, posts, ssid, confusion, attack, common, making, cloudflare, warp, vpn, leak, fragattacks, clarifying, some, aspects, addressing, general, being, within, range, easy, or, hard, abuse, not, both, applicability, old, wep, tkip, protocols, do, attackers, need, know, password, network, two, types, less, more, ones, access, points, clients, matter, which, eap, authentication, method, is, used, multi, channel, mitm, rogue, ap, using, 802, 11w, make, attacks, collaboration, with, wi, fi, companies,

Text of the page (most frequently used words):
the (277), and (67), this (52), that (52), #network (44), can (42), are (39), adversary (29), dns (29), attack (25), all (24), networks (24), client (23), when (19), these (19), for (19), more (17), access (17), also (16), ghz (16), not (15), attacks (15), used (15), some (15), server (15), ssid (14), design (14), eap (14), fragment (14), using (13), which (13), paper (13), have (13), but (13), cache (13), hotspots (13), hotspot (13), victim (13), has (12), flaws (12), frames (12), doesn (12), only (12), other (12), ipv6 (12), mitm (11), same (11), flaw (11), share (10), will (10), with (10), channel (10), two (10), you (10), enterprise (10), then (10), addresses (10), requests (10), 2020 (9), common (9), possible (9), even (9), exploit (9), credentials (9), connect (9), they (9), warp (9), local (9), cloudflare (9), may (8), cve (8), vulnerabilities (8), don (8), about (8), secure (8), security (8), exploiting (7), how (7), windows (7), frame (7), any (7), first (7), from (7), practice (7), their (7), rogue (7), real (7), different (7), point (7), against (7), use (7), clients (7), vulnerability (7), abused (7), less (7), threat (7), than (7), was (7), interfaces (7), servers (7), fd01 (7), db8 (7), 1111 (7), address (6), august (6), 2023 (6), home (6), impact (6), multi (6), position (6), because (6), make (6), further (6), matter (6), method (6), words (6), coffee (6), shop (6), eduroam (6), know (6), both (6), itself (6), 127 (6), into (5), posts (5), september (5), confusion (5), mathy (5), 802 (5), 11w (5), management (5), protection (5), middle (5), attacker (5), see (5), section (5), above (5), harder (5), implementation (5), though (5), require (5), password (5), however (5), vulnerable (5), target (5), traffic (5), means (5), without (5), does (5), model (5), need (5), range (5), website (5), ipv4 (5), support (5), radius (5), band (5), june (4), misconceptions (4), blog (4), finally (4), research (4), machine (4), another (4), own (4), one (4), why (4), particular (4), note (4), briefly (4), were (4), 24586 (4), traditional (4), while (4), based (4), cannot (4), users (4), points (4), intercept (4), created (4), ptk (4), wep (4), combined (4), within (4), user (4), most (4), being (4), vpn (4), supports (4), ssids (4), works (3), atom (3), february (3), july (3), march (3), pinterest (3), facebook (3), blogthis (3), email (3), geplaatst (3), door (3), way (3), aspects (3), like (3), sending (3), instead (3), malicious (3), makes (3), defense (3), encryption (3), block (3), modify (3), encrypted (3), authentication (3), types (3), discovered (3), abusing (3), trivial (3), discussed (3), old (3), post (3), pwd (3), easier (3), methods (3), mentioned (3), time (3), discusses (3), scenario (3), where (3), made (3), detail (3), case (3), connects (3), each (3), uses (3), unique (3), university (3), inject (3), device (3), trust (3), them (3), aps (3), think (3), special (3), whether (3), already (3), broken (3), exploited (3), long (3), tkip (3), patch (3), example (3), aggregation (3), interaction (3), simply (3), hard (3), abuse (3), doing (3), specific (3), leaked (3), still (3), could (3), assign (3), occur (3), often (3), instance (3), high (3), complexity (3), now (3), computers (3), configured (3), loopback (3), represent (3), ethernet (3), found (3), chapv2 (3), heap (2), insecure (2), 2012 (2), comments (2), subscribe (2), october (2), november (2), 2021 (2), 2024 (2), older (2), try (2), out (2), especially (2), people (2), alliance (2), understand (2), academic (2), always (2), easiest (2), clarify (2), thank (2), isn (2), established (2), establish (2), switch (2), accomplished (2), spoofing (2), beacon (2), spoofed (2), enabled (2), meaning (2), won (2), between (2), channels (2), hopefully (2), gets (2), new (2), currently (2), reliably (2), what (2), prevent (2), must (2), experiments (2), typical (2), copying (2), authenticates (2), prevented (2), likely (2), next (2), experiment (2), configure (2), certificates (2), quick (2), nevertheless (2), work (2), exactly (2), just (2), group (2), data (2), least (2), uncommon (2), such (2), universities (2), fact (2), important (2), there (2), difference (2), normal (2), shared (2), clone (2), knowing (2), pairwise (2), keys (2), key (2), needed (2), subsequently (2), should (2), longer (2), protocols (2), immediately (2), affected (2), plaintext (2), biggest (2), 24588 (2), presentation (2), proximity (2), get (2), protocol (2), requires (2), settings (2), fragattacks (2), antenna (2), receive (2), second (2), refer (2), cases (2), bypassed (2), discuss (2), yet (2), issue (2), didn (2), would (2), router (2), multiple (2), leakage (2), updated (2), having (2), actually (2), cvss (2), man (2), spoof (2), responses (2), nearly (2), direct (2), needs (2), random (2), computer (2), perform (2), called (2), over (2), its (2), world (2), highlights (2), models (2), configuration (2), occasionally (2), advertises (2), previous (2), backwards (2), compatibility (2), applies (2), vanhoef (2), powered, blogger, insert, sql, injections, ninja, style, reversing, arm, binaries, rwthctf, trafman, mac, randomization, understanding, overflows, whatsapp, considered, popular, 2011, january, april, december, 2013, 2014, 2015, 2016, 2017, 2018, 2019, archive, happy, testing, hacking, test, tool, went, ask, questions, either, directly, through, realize, papers, dense, whenever, gladly, things, everyone, helped, during, embargo, collaboration, companies, known, rely, 26146, remain, deauthentication, disassociation, disconnect, forces, contain, announcements, enabling, copied, source, side, remark, few, years, ago, collaborated, industry, much, eventually, implemented, unknown, standardize, break, mutual, exploitation, contrast, requirements, able, done, explained, operating, hunch, wrongly, claimed, caused, misunderstanding, leads, clarification, mentions, tested, wasn, explicitly, those, performed, later, identical, moreover, trickier, relying, summarized, clones, injected, worried, remember, targets, relies, bssid, becoming, situation, problematic, isolation, downstream, addressed, forwarding, proxy, arp, service, unable, username, impersonate, authenticated, connecting, observation, distrustful, forms, basis, visitor, exfiltrate, fragmented, unless, spec, let, focus, distrust, explain, who, true, worldwide, someone, visit, awesome, researchers, unfortunately, visitors, connected, under, circumstances, kinds, touched, upon, publicly, among, customers, automatically, provided, details, set, authenticity, verified, ones, transient, gtk, knows, been, passively, decrypt, exotic, theoretic, ignore, asked, attackers, image, musheera, mirani, describes, latest, standards, wpa2, wpa3, completeness, confirm, existed, clear, indicated, deprecated, applicability, context, preconditions, determine, cves, allow, injection, short, overview, complicated, 26139, social, engineering, merely, covers, worry, absolutely, argue, horribly, ancient, result, concern, programming, mistakes, products, echoes, conclusion, our, devastating, quote, easy, matt, parkinson, mean, right, signal, kilometer, documents, nsa, claims, extreme, perfect, conditions, kilometers, simple, external, practically, put, differently, line, states, fragattack, others, receivers, process, aggregated, force, aggregate, none, attacking, sha1, intersection, crypto, colloquially, rc4, cryptographic, primitives, addressing, general, haven, watch, usenix, read, clarifying, tuesday, clouldflare, associated, extra, changed, happened, supported, smooth, handling, disclosure, noticed, reported, saw, weird, behavior, investigate, afterwards, checked, impactful, discussion, fixed, beta, build, 170, available, official, release, included, fix, version, released, initial, interestingly, assigning, really, realizing, installed, virtualbox, virtual, interface, becomes, matches, intuitively, say, low, following, themselves, logical, path, essentially, score, severity, rated, once, looking, return, visits, sent, forward, back, https, protected, completely, unprotected, attacked, com, easily, privacy, websites, visiting, apps, namely, advertise, configuring, configures, referring, behave, private, form, 192, 168, ulas, idea, act, actual, manner, handled, securely, handle, everything, expected, adapter, connection, suffix, kuleuven, netbios, tcpip, enable, tunnel, seen, executing, ipconfig, create, offers, free, tricked, leaking, making, leak, thursday, interesting, part, practical, given, expect, many, importance, considering, shows, verifying, checking, additionally, purposes, scenarios, consider, warn, potential, insecurity, lesson, might, seem, useful, measurements, shown, said, due, lower, usually, below, therefore, separate, disabled, enhance, typically, equipment, surveys, wardrives, 250, 000, average, certainly, compared, broadcast, limited, scraped, public, profiles, execute, usernames, passwords, outsider, kind, additional, increase, assumed, capability, obtain, decryption, required, master, pmk, cause, after, generic, pre, secret, spotted, nice, something, panic, wednesday, tools, publications, pages, professor, leuven, belgium, postdoc, nyu, open, consultancy,

Text of the page (random words):
cloudflare warp vpn leak dns requests cloudflare offers a free vpn client called cloudflare warp i found that its windows client can be tricked into leaking all dns requests the adversary can then spoof dns responses and intercept nearly all traffic to exploit the vulnerability the adversary needs to create a rogue wi fi or ethernet network that supports ipv6 when the local network supports ipv6 all dns requests are leaked why are dns requests leaked when you enable the vpn tunnel the cloudflare warp client will configure a local dns server this can be seen when executing ipconfig ethernet adapter ethernet connection specific dns suffix cs kuleuven be dns servers fd01 db8 1111 2 fd01 db8 1111 3 127 0 2 2 127 0 2 3 netbios over tcpip enabled the idea is that the cloudflare warp client will act as a local dns server this local dns server will perform the actual dns requests in a secure manner for ipv4 the special ip addresses 127 0 2 2 and 127 0 0 3 are configured as the dns server these ip addresses refer to the windows computer itself they re called loopback addresses so when the network only supports ipv4 these loopback ip addresses are used for the dns server and all dns requests are handled by the cloudflare warp client the warp client will then securely handle the dns requests so everything works as expected when using ipv4 the cloudflare warp client also configures the ipv6 addresses fd01 db8 1111 2 and fd01 db8 1111 3 as dns servers when the local network supports ipv6 these addresses will be used but these are not loopback addresses referring to the windows machine itself these special are unique local addresses ulas this means they behave the same as private ipv4 address of the form 192 168 x y in other words these two ipv6 addresses represent random computers in the local network they don t represent the windows computer itself all combined the cloudflare warp client is configuring two random ipv6 computers in the local network as dns servers namely the computers fd01 db8 1111 2 and fd01 db8 1111 3 are configured as dns servers so a rogue wi fi network simply needs to advertise support for ipv6 assign itself the ipv6 address fd01 db8 1111 2 and then it will receive all dns requests the leakage of dns requests has a direct impact on the user s privacy you can now see which websites the victim is visiting which apps are being used and so on but there s more once the adversary can intercept dns requests they can also spoof dns responses and by doing so the adversary can easily intercept nearly all ip based traffic of the victim for instance if the victim is looking up the ip address of website com the adversary can return the ip address of their own server when the victim now visits this website all traffic will be sent to the adversary s server and the adversary can forward it to the real server and back if the website uses https then traffic is still protected but the vpn itself is now completely bypassed and all unprotected protocols can be subsequently attacked the severity was rated as high this matches the cvss score of 7 4 it doesn t require user interaction and has a high attack complexity intuitively i would actually say it has a low attack complexity but cvss has the following example for high attack complexity the attacker must inject themselves into the logical network path e g a man in the middle attack and exploiting the vulnerability essentially requires a mitm position another harder to exploit flaw a second issue was that the clouldflare warp client only updated the dns servers of the first two network interfaces if you have more than two network interfaces the dns servers associated to these extra network interfaces didn t get changed this means a rogue wi fi network could assign itself as the dns server and if the victim has more than two network interfaces windows would use the adversary s wi fi router as the dns server this happened even when the local network only supported ipv4 having multiple network interfaces can occur more often than you think for instance if the victim installed virtualbox then a virtual network interface is created and the attack becomes possible to patch this initial vulnerability the windows client was updated to assign the dns servers 127 0 2 2 and 127 0 0 3 to all network interfaces interestingly it was no longer assigning ipv6 addresses for the dns server so that patch without us really realizing it yet also prevented the above ipv6 based attack all combined these two vulnerabilities were fixed in beta build 2023 5 170 1 which was made available on may 12 2023 the first official release that included the fix was version 2023 7 7 0 which was released on july 7 2023 discussion i first noticed the multiple interfaces dns leakage flaw and immediately reported that while doing so i already saw some weird ipv6 behavior but i didn t have time to investigate it afterwards i also checked the ipv6 issue and also discovered this more impactful attack finally i d like to thank cloudflare for the smooth handling of this vulnerability and disclosure geplaatst door mathy op 18 26 email this blogthis share to x share to facebook share to pinterest tuesday 18 may 2021 fragattacks clarifying some aspects if you haven t yet read about this research then watch my usenix security presentation in this blog post i ll discuss some aspects in more detail than i could in the paper addressing general misconceptions none of the flaws are in the cryptographic primitives used by wi fi in other words we re not attacking rc4 or sha1 the design flaws are instead at the intersection of crypto and protocol design which people colloquially refer to as the encryption used in wi fi in other words the encryption of wi fi is still being broken and in some cases bypassed the aggregation design flaw cve 2020 24588 can be abused to make receivers process a normal frame as if it were an aggregated frame it cannot be abused to force a device to aggregate frames both clients and access points aps are affected some flaws are more common in clients while others are more common in aps being within range just like practically all wi fi vulnerabilities you need to be in proximity of the victim to exploit the discovered flaws put differently as the second line of the fragattack website states an adversary that is within range of a victim s wi fi network can abuse these vulnerabilities this doesn t mean the adversary has to be right next to the target network a simple external antenna can be used to receive a wi fi signal up to one kilometer in leaked documents the nsa even claims that a range of more than 12 kilometers is possible though that extreme range is only possible in perfect conditions antenna made by matt parkinson easy or hard to abuse why not both the design flaws are on their own hard to exploit to quote the fragattacks website the design flaws are hard to abuse because doing so requires user interaction or is only possible when using uncommon network settings as a result in practice the biggest concern are the programming mistakes in wi fi products this echoes the conclusion in the paper our implementation specific vulnerabilities are the most devastating so it s the implementation flaws we have to worry about why because exploiting some of them is absolutely trivial an adversary that is within proximity of the target network can then simply inject plaintext frames it cannot get any easier than that in fact one can argue that this is even easier than exploiting the horribly broken and ancient wep protocol it gets more complicated when design flaws are combined with implementation flaws the biggest example is when the aggregation design flaw cve 2020 24588 in clients is combined with implementation flaw cve 2020 26139 in access points in this scenario the aggregation design flaw can be exploited without user interaction i e without social engineering that means the adversary merely has to be within range of the target network section 6 6 in the paper discusses this in further detail and the presentation also briefly covers this as further context i ve also created a short overview with attacks and their preconditions a quick way to determine whether it s important to immediately patch a device is to see whether it s affected by any of the cves that allow plaintext injection applicability to the old wep and tkip protocols the paper describes the impact of the vulnerabilities on the latest standards such as wpa2 and wpa3 for completeness it also briefly discusses wep and tkip to confirm that some of these vulnerabilities have existed for a long time it s hopefully clear though as also indicated in the paper that wep and tkip should no longer be used they re both insecure old and deprecated by the wi fi alliance image from musheera mirani do attackers need to know the password of the network some have asked me whether any of the attacks require knowing the pairwise transient keys ptk or group key gtk of the victim that s not the case if an attacker knows the ptk it means wi fi security has already been broken the adversary can use the ptk to passively decrypt all data all the attacks work without knowing the password of the network the cache attack cve 2020 24586 does have a more exotic threat model when an ap is vulnerable this flaw can be exploited in hotspot 2 0 or enterprise networks as long as the adversary also has credentials that are needed to connect to this network but even in this threat model the adversary does not know the ptk of the victim and the adversary also does not know the credentials of the victim finally when a client is vulnerable to the fragment cache attack it can only be exploited when the client first connects to the adversary s network and subsequently connects to the target network this threat model to exploit cve 2020 24586 in a client is currently a theoretic threat model and you can ignore it in practice two types of hotspots the less secure and more secure ones the fragment cache design flaw can only be abused against hotspots it s important to note that there are two kinds of hotspots the traditional coffee shop hotspot and the new hotspot 2 0 this difference is touched upon in section 5 1 of the paper the coffee shop hotspots are normal home networks where the password of the network is shared publicly among customers and you can think of hotspot 2 0 networks as special enterprise networks where users are automatically provided unique credentials for more details see section 2 4 in the paper the coffee shop hotspots are less secure because an adversary can set up a rogue clone of the hotspot and intercept traffic the hotspot 2 0 networks are more secure because the authenticity of the network is verified meaning a rogue clone cannot be created by an adversary to exploit aps that are vulnerable to the fragment cache vulnerability we target hotspot 2 0 networks to exploit clients that are vulnerable to the fragment cache vulnerability the attack makes use of traditional coffee shop hotspots in other words these two types of hotspots are abused under different circumstances hotspots 2 0 vs the fragment cache of access points let s first focus on hotspot 2 0 security and enterprise networks in these networks users may distrust each other this is the easiest to explain in hotspot networks i don t know who the other users are and i don t trust them the same can be true in enterprise networks such as eduroam a network used by universities worldwide with eduroam someone from university a can visit university b and connect to the eduroam network using the credentials of their home network awesome but i don t trust researchers from other universities though unfortunately these visitors can connect to the same network that i m using in fact they can connect to exactly the same access point that i m connected to but i don t trust them the above situation doesn t have to be problematic by using client isolation downstream group addressed forwarding and a proxy arp service clients are unable to attack each other see the hotspot 2 0 spec note that in these networks each client uses their own unique credentials e g username and password to access the network and that an adversary cannot impersonate the eduroam network i e the network is authenticated while connecting however the observation that distrustful users connect to the same access point in these hotspots forms the basis of how the fragment cache vulnerability cve 2020 24586 is abused against access points in particular the visitor attacker from the other university can connect to the same access point that i m using inject a malicious fragment into the fragment cache of the ap which can then be abused to attack me in practice this can be abused to exfiltrate data that i m sending at least when my device is sending fragmented wi fi frames which is uncommon unless wi fi 6 is used secure wi fi hotspots are becoming more common hotspots vs the fragment cache of clients exploiting the fragment cache design flaw cve 2020 24586 against clients is trickier the paper discusses a scenario where this is made possible by relying on traditional coffee shop hotspots briefly summarized the adversary clones the coffee shop hotspot using a spoofed bssid and the victim connects based on the real ssid then a malicious fragment is injected into the fragment cache of the client this attack is academic and will be discussed in another blog post in more detail in any case i m not worried about it in practice just remember that when abusing the fragment cache design flaw against a client the attack relies on traditional hotspots while abusing the fragment cache design flaw against an access point targets hotspot 2 0 and or enterprise wi fi networks doesn t matter which eap authentication method is used all attacks are possible no matter how the client authenticates the network in other words attacks are identical against home and enterprise networks moreover it doesn t matter which eap method you use in an enterprise network all attacks are possible and work exactly the same way no matter which eap method is used note that the paper briefly mentions an experiment with eap pwd with this eap method you don t have to configure certificates which makes it easier to do a quick experiment with eap pwd nevertheless attacks were also tested when using other eap methods but this wasn t explicitly mentioned in the paper as those experiments were performed at a later point in time i do have a hunch why some wrongly claimed that attacks are prevented by using eap in particular this is likely caused by a misunderstanding of how some attacks require a machine in the middle position this leads me to the next clarification multi channel mitm vs rogue ap abusing the design flaws on their own is not trivial in contrast to the implementation flaws which can be trivial to exploit one of the requirements is that the adversary must be able to block and modify en...