Un cheval de Troie découvert sous OS X, Réactions à la news du 31-10-2007

[Lionel]

Source : Intego

Intego a lancé une alerte au sujet d'un cheval de Troie. Il a été découvert sur certains sites pornographiques.
Basé sur la crédulité de certains, il va proposer une mise à jour permettant d'avoir accès à l'intégralité du site. Un fichier sous forme de .dmg sera alors téléchargé, et le mot de passe administrateur demandé.
En fait, le logiciel plutôt que d'installer quoique ce soit, va changer le DNS de la machine.
Une fois le DNS changé, il sera possible aux pirates d'orienter les victimes vers de faux sites permettant de réaliser des phishings aussi parfaits que possible. Ceci peut toucher des comptes Paypal, Ebay ou encore associés à des banques.
Il installe également une routine vérifiant régulièrement que le DNS n'a pas été entre temps modifié et veille à remettre le malicieux.

Pour s'en prémunir, il suffit de se rappeler d'une règle élémentaire. Ne téléchargez pas n'importe quoi, et ne rentrez votre mot de passe admin que lorsque vous êtes certain que c'est à bon escient.
Il y a hélas des chances que ce type d'attaque n'aille en augmentant et se fasse de plus en plus pernicieuse avec le temps, les parts de marché d'Apple augmentant.




Je sais que c'est un sujet toujours ultra sensible dans la communauté Mac. Pour une fois, traitez le froidement et sans excitation. Merci d'avance.

[trouspinette]

Un truc qui n'a pas grand chose à voir, mais Bravo Macbidouille, vous êtes QUASI 100% RFC Compliant sur le domaine.

Le seul truc "qui ne va spas" est le SPF record => WARN SPF record Your domain does not have an SPF record.

Well done; DNS très bien géré


Category Status Test Name Information
Parent PASS Missing Direct Parent check OK. Your direct parent zone exists, which is good. Some domains (usually third or fourth level domains, such as example.co.us) do not have a direct parent zone ('co.us' in this example), which is legal but can cause confusion.
INFO NS records at parent servers Your NS records at the parent servers are:

filter.dc-zone.net. [212.43.222.193] [TTL=172800] [FR]
mbserv3.macbidouille.com. [212.27.33.185] [TTL=172800] [FR]
[These were obtained from g.gtld-servers.net]
PASS Parent nameservers have your nameservers listed OK. When someone uses DNS to look up your domain, the first step (if it doesn't already know about your domain) is to go to the parent servers. If you aren't listed there, you can't be found. But you are listed there.
PASS Glue at parent nameservers OK. The parent servers have glue for your nameservers. That means they send out the IP address of your nameservers, as well as their host names.
PASS DNS servers have A records OK. All your DNS servers either have A records at the zone parent servers, or do not need them (if the DNS servers are on other TLDs). A records are required for your hostnames to ensure that other DNS servers can reach your DNS servers. Note that there will be problems if your DNS servers do not have these same A records.
NS INFO NS records at your nameservers Your NS records at your nameservers are:

filter.dc-zone.net. [212.43.222.193] [TTL=86400]
mbserv3.macbidouille.com. [212.27.33.185] [TTL=86400]
PASS Open DNS servers OK. Your DNS servers do not announce that they are open DNS servers. Although there is a slight chance that they really are open DNS servers, this is very unlikely. Open DNS servers increase the chances that of cache poisoning, can degrade performance of your DNS, and can cause your DNS servers to be used in an attack (so it is good that your DNS servers do not appear to be open DNS servers).
PASS Mismatched glue OK. The DNS report did not detect any discrepancies between the glue provided by the parent servers and that provided by your authoritative DNS servers.
PASS No NS A records at nameservers OK. Your nameservers do include corresponding A records when asked for your NS records. This ensures that your DNS servers know the A records corresponding to all your NS records.
PASS All nameservers report identical NS records OK. The NS records at all your nameservers are identical.
PASS All nameservers respond OK. All of your nameservers listed at the parent nameservers responded.
PASS Nameserver name validity OK. All of the NS records that your nameservers report seem valid (no IPs or partial domain names).
PASS Number of nameservers OK. You have 2 nameservers. You must have at least 2 nameservers (RFC2182 section 5 recommends at least 3 nameservers), and preferably no more than 7.
PASS Lame nameservers OK. All the nameservers listed at the parent servers answer authoritatively for your domain.
PASS Missing (stealth) nameservers OK. All 2 of your nameservers (as reported by your nameservers) are also listed at the parent servers.
PASS Missing nameservers 2 OK. All of the nameservers listed at the parent nameservers are also listed as NS records at your nameservers.
PASS No CNAMEs for domain OK. There are no CNAMEs for macbidouille.com. RFC1912 2.4 and RFC2181 10.3 state that there should be no CNAMEs if an NS (or any other) record is present.
PASS No NSs with CNAMEs OK. There are no CNAMEs for your NS records. RFC1912 2.4 and RFC2181 10.3 state that there should be no CNAMEs if an NS (or any other) record is present.
PASS Nameservers on separate class C's OK. You have nameservers on different Class C (technically, /24) IP ranges. You must have nameservers at geographically and topologically dispersed locations. RFC2182 3.1 goes into more detail about secondary nameserver location.
PASS All NS IPs public OK. All of your NS records appear to use public IPs. If there were any private IPs, they would not be reachable, causing DNS delays.
PASS TCP Allowed OK. All your DNS servers allow TCP connections. Although rarely used, TCP connections are occasionally used instead of UDP connections. When firewalls block the TCP DNS connections, it can cause hard-to-diagnose problems.
PASS Single Point of Failure OK. It appears that your nameservers are on separate physical servers, and we did not detect the same firewall in front of all servers. We check this mainly because some people have 2 NS records that point to different IPs on the same DNS server.
INFO Nameservers versions Your nameservers have the following versions:

212.43.222.193: ""
212.27.33.185: No version info available (refused).
PASS Stealth NS record leakage Your DNS servers do not leak any stealth NS records (if any) in non-NS requests.
SOA INFO SOA record Your SOA record [TTL=86400] is:

Primary nameserver: filter.dc-zone.net.
Hostmaster E-mail address: root.filter.dc-zone.net.
Serial #: 2007081602
Refresh: 43200
Retry: 3600
Expire: 1814400
Default TTL: 86400
PASS NS agreement on SOA serial # OK. All your nameservers agree that your SOA serial number is 2007081602. That means that all your nameservers are using the same data (unless you have different sets of data with the same serial number, which would be very bad)! Note that the DNSreport only checks the NS records listed at the parent servers (not any stealth servers).
PASS SOA MNAME Check OK. Your SOA (Start of Authority) record states that your master (primary) name server is: filter.dc-zone.net.. That server is listed at the parent servers, which is correct.

PASS SOA RNAME Check OK. Your SOA (Start of Authority) record states that your DNS contact E-mail address is: [email protected]. (techie note: we have changed the initial '.' to an '@' for display purposes).
PASS SOA Serial Number OK. Your SOA serial number is: 2007081602. This appears to be in the recommended format of YYYYMMDDnn, where 'nn' is the revision. So this indicates that your DNS was last updated on 16 Aug 2007 (and was revision #2). This number must be incremented every time you make a DNS change.
PASS SOA REFRESH value OK. Your SOA REFRESH interval is : 43200 seconds. This seems normal (about 3600-7200 seconds is good if not using DNS NOTIFY; RFC1912 2.2 recommends a value between 1200 to 43200 seconds (20 minutes to 12 hours)). This value determines how often secondary/slave nameservers check with the master for updates.
PASS SOA RETRY value OK. Your SOA RETRY interval is : 3600 seconds. This seems normal (about 120-7200 seconds is good). The retry value is the amount of time your secondary/slave nameservers will wait to contact the master nameserver again if the last attempt failed.
PASS SOA EXPIRE value OK. Your SOA EXPIRE time: 1814400 seconds. This seems normal (about 1209600 to 2419200 seconds (2-4 weeks) is good). RFC1912 suggests 2-4 weeks. This is how long a secondary/slave nameserver will wait before considering its DNS data stale if it can't reach the primary nameserver.
PASS SOA MINIMUM TTL value OK. Your SOA MINIMUM TTL is: 86400 seconds. This seems normal (about 3,600 to 86400 seconds or 1-24 hours is good). RFC2308 suggests a value of 1-3 hours. This value used to determine the default (technically, minimum) TTL (time-to-live) for DNS entries, but now is used for negative caching.
MX INFO MX Record Your 1 MX record is:

10 dcserv1.dimcab.com. [TTL=86400] IP=212.43.240.113 [TTL=43200] [FR]
PASS Low port test OK. Our local DNS server that uses a low port number can get your MX record. Some DNS servers are behind firewalls that block low port numbers. This does not guarantee that your DNS server does not block low ports (this specific lookup must be cached), but is a good indication that it does not.
PASS Invalid characters OK. All of your MX records appear to use valid hostnames, without any invalid characters.
PASS All MX IPs public OK. All of your MX records appear to use public IPs. If there were any private IPs, they would not be reachable, causing slight mail delays, extra resource usage, and possibly bounced mail.
PASS MX records are not CNAMEs OK. Looking up your MX record did not just return a CNAME. If an MX record query returns a CNAME, extra processing is required, and some mail servers may not be able to handle it.
PASS MX A lookups have no CNAMEs OK. There appear to be no CNAMEs returned for A records lookups from your MX records (CNAMEs are prohibited in MX records, according to RFC974, RFC1034 3.6.2, RFC1912 2.4, and RFC2181 10.3).
PASS MX is host name, not IP OK. All of your MX records are host names (as opposed to IP addresses, which are not allowed in MX records).
INFO Multiple MX records NOTE: You only have 1 MX record. If your primary mail server is down or unreachable, there is a chance that mail may have troubles reaching you. In the past, mailservers would usually re-try E-mail for up to 48 hours. But many now only re-try for a couple of hours. If your primary mailserver is very reliable (or can be fixed quickly if it goes down), having just one mailserver may be acceptable.
PASS Differing MX-A records OK. I did not detect differing IPs for your MX records (this would happen if your DNS servers return different IPs than the DNS servers that are authoritative for the hostname in your MX records).
PASS Duplicate MX records OK. You do not have any duplicate MX records (pointing to the same IP). Although technically valid, duplicate MX records can cause a lot of confusion, and waste resources.
PASS Reverse DNS entries for MX records OK. The IPs of all of your mail server(s) have reverse DNS (PTR) entries. RFC1912 2.1 says you should have a reverse DNS for all your mail servers. It is strongly urged that you have them, as many mailservers will not accept mail from mailservers with no reverse DNS entry. Note that this information is cached, so if you changed it recently, it will not be reflected here (see the www.DNSstuff.com Reverse DNS Tool for the current data). The reverse DNS entries are:

113.240.43.212.in-addr.arpa dcserv1.dimcab.com. [TTL=3600]
Mail PASS Connect to mail servers OK: I was able to connect to all of your mailservers.
PASS Mail server host name in greeting OK: All of your mailservers have their host name in the greeting:

dcserv1.dimcab.com:<br /> 220 dcserv1.dimcab.com ESMTP Postfix <br />
PASS Acceptance of NULL <> sender OK: All of your mailservers accept mail from "<>". You are required (RFC1123 5.2.9) to receive this type of mail (which includes reject/bounce messages and return receipts).
PASS Acceptance of postmaster address OK: All of your mailservers accept mail to [email protected] (as required by RFC822 6.3, RFC1123 5.2.7, and RFC2821 4.5.1).
PASS Acceptance of abuse address OK: All of your mailservers accept mail to [email protected].
PASS Acceptance of domain literals OK: All of your mailservers accept mail in the domain literal format (user@[212.43.240.113]).
PASS Open relay test OK: All of your mailservers appear to be closed to relaying. This is not a thorough check, you can get a thorough one here.

dcserv1.dimcab.com OK: 554 5.7.1 <Not.abuse.see.www.DNSreport.com.from.IP.90.49.132.220@DNSreport.com>: Relay access denied <br />
WARN SPF record Your domain does not have an SPF record. This means that spammers can easily send out E-mail that looks like it came from your domain, which can make your domain look bad (if the recipient thinks you really sent it), and can cost you money (when people complain to you, rather than the spammer). You may want to add an SPF record ASAP, as 01 Oct 2004 was the target date for domains to have SPF records in place (Hotmail, for example, started checking SPF records on 01 Oct 2004).
WWW
INFO WWW Record Your www.macbidouille.com A record is:

www.macbidouille.com. CNAME mbserv4.macbidouille.com. [TTL=86400]
mbserv4.macbidouille.com. A 212.43.222.205 [TTL=86400] [FR]
PASS All WWW IPs public OK. All of your WWW IPs appear to be public IPs. If there were any private IPs, they would not be reachable, causing problems reaching your web site.
PASS CNAME Lookup OK. You do have a CNAME record for www.macbidouille.com, which can cause some confusion. However, this is legal. Your CNAME entry also returns the A record for the CNAME entry, which is good -- otherwise, it would require an extra DNS lookup, which slightly delays the initial access to the website and use extra bandwidth. Note that if the CNAME points to another CNAME, it will likely cause problems.
INFO Domain A Lookup Your macbidouille.com A record is:

macbidouille.com. A 212.43.222.205 [TTL=86400]