Re: [Full-disclosure] pidgin OTR information leakage
On Feb 27, 2012, at 2:37 PM, Michele Orru wrote: I think you didn't understood the content of the advisory. If there are 10 non-root users in an Ubuntu machine for example, if user 1 is using pidgin with OTR compiled with DBUS, then user 2 to 10 can see what user 1 pidgin conversation. This is not what the OP or CVE describe: plaintext. This makes it possible for attackers that have gained user-level access on a host, to listen in on private conversations associated with the victim account. Which I read as: if I compromise user1's account then I can snoop user1's DBUS sessions. It says nothing about me being able to snoop user2's sessions. The leading phrase about attackers gaining user-level access implies that legitimate users on a system are not a relevant issue. I believe that clarification is in order. -- Rich Pieri rati...@mit.edu MIT Laboratory for Nuclear Science ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Re: [Full-disclosure] pidgin OTR information leakage
On 02/27/2012 11:23 PM, devn...@vonage.com wrote: I believe that clarification is in order. Indeed it is. The original post mentions a same-user attack vector which is very misleading as to what the real problem here is. And it boils down to this: Once a process sends private info over DBUS there is no way to control where this ends up (which apps are the qualified receivers) or what the receivers do with it. So, if for example the user selects not to log OTR plaintext (so that this sensitive information doesn't touch the hard drive) another application on the other end of DBUS might choose to do something different (and not by malicious intent). There is no way to enforce the same security policy on the sender and the receivers. How this could be exploited by attackers or what forensic evidence DBUS snooping leaves are of much less importance than the above privacy issue. There is a very good discussion on the pidgin ticket page: http://developer.pidgin.im/ticket/14830 Also, I've made some updates to our post, to make it clearer as to what this issue is about: http://census-labs.com/news/2012/02/25/libpurple-otr-info-leak/ If there are still questions, I'll be happy to answer them. Hope this clarifies things a bit, Dimitris ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Re: [Full-disclosure] pidgin OTR information leakage
On 02/28/2012 12:14 AM, Dimitris Glynos wrote: On 02/27/2012 11:23 PM, devn...@vonage.com wrote: I believe that clarification is in order. Indeed it is. The original post mentions a same-user attack vector which is very misleading as to what the real problem here is. And it boils down to this: Once a process sends private info over DBUS there is no way to control where this ends up (which apps are the qualified receivers) or what the receivers do with it. This should be: Once a process *broadcasts* private info over DBUS there is no way to control where this ends up (which apps are the qualified receivers) or what the receivers do with it. So, if for example the user selects not to log OTR plaintext (so that this sensitive information doesn't touch the hard drive) another application on the other end of DBUS might choose to do something different (and not by malicious intent). There is no way to enforce the same security policy on the sender and the receivers. How this could be exploited by attackers or what forensic evidence DBUS snooping leaves are of much less importance than the above privacy issue. There is a very good discussion on the pidgin ticket page: http://developer.pidgin.im/ticket/14830 Also, I've made some updates to our post, to make it clearer as to what this issue is about: http://census-labs.com/news/2012/02/25/libpurple-otr-info-leak/ If there are still questions, I'll be happy to answer them. Hope this clarifies things a bit, Dimitris ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
[Full-disclosure] pidgin OTR information leakage
Pidgin transmits OTR (off-the-record) conversations over DBUS in plaintext. This makes it possible for attackers that have gained user-level access on a host, to listen in on private conversations associated with the victim account. Pidgin is a popular Instant Messenger application that runs on a wide variety of platforms including Windows and Linux. The pidgin-otr plugin enables users to communicate securely over any Instant Messenger network using the “Off-the-record” messaging protocol. If Pidgin is compiled with DBUS support and there is a DBUS session daemon running on the system, then all messages that are typed into Pidgin and messages received through Pidgin are broadcasted on DBUS. The reasoning behind this is to allow for third party applications, such as desktop widgets to process these messages (e.g. create an animation when a message arrives). However, among the messages transmitted over DBUS one also finds OTR conversations in plaintext form. This is a security problem, as the private OTR messages may leak to other (unrelated) processes that are executing with the Pidgin user’s rights. A more detailed advisory and proof-of-concept script can be found here: http://census-labs.com/news/2012/02/25/pidgin-otr-info-leak/ The Pidgin and pidgin-otr development teams have been contacted about this issue and we anticipate a fix in a coordinated future release. The Common Vulnerabilities and Exposures (CVE) project has assigned candidate name CVE-2012-1257 to this issue. Disclosure Timeline --- Vendor Contact(s): December 20th, 2011 CVE assignment:February 21st, 2012 Public Disclosure: February 25th, 2012 Kind regards, Dimitris Glynos -- http://census-labs.com -- IT security research, development and services ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Re: [Full-disclosure] pidgin OTR information leakage
On 02/25/2012 06:31 PM, Dimitris Glynos wrote: Pidgin transmits OTR (off-the-record) conversations over DBUS in plaintext. This makes it possible for attackers that have gained user-level access on a host, to listen in on private conversations associated with the victim account. As noted by Peter Lawler this should really be referenced as a libpurple issue and not a pidgin one. You may find the updated advisory here: http://census-labs.com/news/2012/02/25/libpurple-otr-info-leak/ (old URL is valid too) Best regards, Dimitris Glynos -- http://census-labs.com -- IT security research, development and services ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Re: [Full-disclosure] pidgin OTR information leakage
2012/2/25 Dimitris Glynos dimit...@census-labs.com: Pidgin transmits OTR (off-the-record) conversations over DBUS in plaintext. This makes it possible for attackers that have gained user-level access on a host, to listen in on private conversations associated with the victim account. Basically, you're saying that if I have the rights of a user on a machine, I can access the private conversations of that user? Ooooh no. Well, I can also copy his keyfiles, no? And I can alter his settings. And spawn fake Update didn't work, please enter root password to proceed windows. I could alter his ~/.bashrc so that whenever he launches sudo or su, a script is launched instead that grabs his password. So, please, what's the point? ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Re: [Full-disclosure] pidgin OTR information leakage
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Jann Horn wrote: 2012/2/25 Dimitris Glynos dimit...@census-labs.com: Pidgin transmits OTR (off-the-record) conversations over DBUS in plaintext. This makes it possible for attackers that have gained user-level access on a host, to listen in on private conversations associated with the victim account. Basically, you're saying that if I have the rights of a user on a machine, I can access the private conversations of that user? Ooooh no. Well, I can also copy his keyfiles, no? And I can alter his settings. And spawn fake Update didn't work, please enter root password to proceed windows. I could alter his ~/.bashrc so that whenever he launches sudo or su, a script is launched instead that grabs his password. So, please, what's the point? I think you didn't understood the content of the advisory. If there are 10 non-root users in an Ubuntu machine for example, if user 1 is using pidgin with OTR compiled with DBUS, then user 2 to 10 can see what user 1 pidgin conversation. Simple as that, without impersonating user 1 or knowing his password. Cheers antisnatchor ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/ -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPS9tfAAoJEBgl8Z+oSxe4fv8IAIHrER/TssgDxUmQrpcs11Ud eYdxLG897aa7plBwi8bABSVR/0moO4cH0w3dvcgIYJ1kSlxiy6NLqlGi9SF6biAx Yw4uDDeaQggO9CMS8FX/Dn8JNhZUxQ47C0M4hydd8Irg5FPPUBRDcXkcH5MjI35v GcbSx2MEN5YrSvn4C6z2M3MJcuyhROlWfsa68cBc3EVIe4CjWTK1NLxCidXLrn8V aXtGOpnrXZPoJeNjhCQGvhnAUMdn2W5PQjF24f6hzqb8vHkF7Y0ZunD9IxoWhnMU sNGCcUNAEEDXfGUV6LtkwZOP1l6W7bZTRNqT7C8Jsp/K4Pfbit+ALXIhIlQZCds= =zebT -END PGP SIGNATURE- ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Re: [Full-disclosure] pidgin OTR information leakage
On Mon, Feb 27, 2012 at 3:21 PM, Rich Pieri rati...@mit.edu wrote: On Feb 27, 2012, at 2:37 PM, Michele Orru wrote: I think you didn't understood the content of the advisory. If there are 10 non-root users in an Ubuntu machine for example, if user 1 is using pidgin with OTR compiled with DBUS, then user 2 to 10 can see what user 1 pidgin conversation. This is not what the OP or CVE describe: plaintext. This makes it possible for attackers that have gained user-level access on a host, to listen in on private conversations associated with the victim account. Which I read as: if I compromise user1's account then I can snoop user1's DBUS sessions. It says nothing about me being able to snoop user2's sessions. The leading phrase about attackers gaining user-level access implies that legitimate users on a system are not a relevant issue. I tend to agree with you, and question if that is in fact true (it may well be, my apologies in advance). DBUS is on my list of things to probe, prod, and attatck due to data sharing. But I'd be really surprised if data was available across distinct user sessions. Unix/Linux are usually very good a separating processes and sessions so that data does not comingle. Jeff ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Re: [Full-disclosure] pidgin OTR information leakage
On Mon, Feb 27, 2012 at 10:27 PM, Jeffrey Walton noloa...@gmail.com wrote: On Mon, Feb 27, 2012 at 3:21 PM, Rich Pieri rati...@mit.edu wrote: On Feb 27, 2012, at 2:37 PM, Michele Orru wrote: I think you didn't understood the content of the advisory. If there are 10 non-root users in an Ubuntu machine for example, if user 1 is using pidgin with OTR compiled with DBUS, then user 2 to 10 can see what user 1 pidgin conversation. This is not what the OP or CVE describe: plaintext. This makes it possible for attackers that have gained user-level access on a host, to listen in on private conversations associated with the victim account. Which I read as: if I compromise user1's account then I can snoop user1's DBUS sessions. It says nothing about me being able to snoop user2's sessions. The leading phrase about attackers gaining user-level access implies that legitimate users on a system are not a relevant issue. I tend to agree with you, and question if that is in fact true (it may well be, my apologies in advance). DBUS is on my list of things to probe, prod, and attatck due to data sharing. But I'd be really surprised if data was available across distinct user sessions. Unix/Linux are usually very good a separating processes and sessions so that data does not comingle. Jeff ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/ Exploitation Notes For the purpose of explaining the exploitation impact of this bug we will focus on a popular libpurple-based application, Pidgin. To snoop in on a Pidgin user’s conversation a remote attacker would need to connect to the DBUS daemon that is responsible for the user’s session. There are at least two ways to achieve this. The first one is to exploit an application that runs within the same desktop session as Pidgin. This application would have inherited the necessary DBUS_SESSION_BUS_ADDRESS environmental variable and will thus be able to connect to the DBUS daemon over a unix socket without a problem. The second way is to compromise the user’s account in some way and steal the DBUS_SESSION_BUS_ADDRESS value. There are multiple ways of acquiring the value for this variable, one of them being through /proc/pid/environ(which is accessible to processes of the same owner), and another being through a file in ~/.dbus/session-bus/. Using this value, the attacker will now be able to connect to DBUS with applications that are not part of the desktop session. Please note that the above methods do not require any control over the Pidgin process (ptrace or other). so you either need to able to dump the environment variable from a process run by the victim, or read files which AFAIK only the victim(and root ofc) has access to. did I miss anything? -- Ferenc Kovács @Tyr43l - http://tyrael.hu ___ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
