4 ms·

> And if the target uses sudo at all you don't even need an exploit! Why would a target executable use sudo? There are proper mechanisms for automated elevatio

by hnlmorg 7mo ago

> And if the target uses sudo at all you don't even need an exploit! Why would a target executable use sudo? There are proper mechanisms for automated elevation of permissions and sudo isn’t it. sudo is designed for user interactivity. And by default prompts for a password. However some people get lazy and disable the password entry requirement.

IshKebab 7mo ago
A target user. If you get local code execution on the account of a user that uses sudo you can trivially got root. Doesn't matter if they disabled the password authentication or not.
- hnlmorg 7mo ago
  Of course it matters if they disabled password authentication. If you require password authentication when running sudo then an attacker has to find a RCE exploit and then crack a password. Which is waaay beyond any effort the average attacker is willing to invest. Because At that point, root access isn’t really worth the effort. An attacker will probably just use the host for sending spam emails, bot / DDoS traffic or look for other daemons they can jump to which weren’t web accessible (eg a database). And furthermore, if you’ve got a RCE in a daemon then that code is the running as the daemons’ user. Which shouldn’t be in the sudoers file (eg wheel group) to begin with.
  - IshKebab 7mo ago
    > If you require password authentication when running sudo then an attacker has to find a RCE exploit and then crack a password. Nope! Just alias sudo to something that logs the password.
    - gamer191 7mo ago
      Interesting. If that’s possible (I haven’t tested it, but I’m sure it is) then you wouldn’t even need to log the password. You could just alias sudo to a bash script that runs your malicious payload using the real sudo. Then the user would run the command, be prompted for their password by the real sudo, and be none the wiser that a malicious script has just been executed For what it’s worth, Windows’ security model says it’s not an exploit that programs can grant themselves admin rights if the user is an admin (https://github.com/hfiref0x/UACME https://github.com/hfiref0x/UACME). But afaik Linux doesn’t have that model so it is a bit of an issue that this is possible
      - hnlmorg 7mo ago
        > Interesting. If that’s possible It’s not possible. At least not unless those users have already borked their own system. The previous poster was clutching at straws.
        IshKebab 7mo ago
        Of course it's possible. I've tried it. It works. It's just standard Unix features. What makes you think it isn't possible?
        hnlmorg 7mo ago
        For the reasons I’ve already stated: daemons don’t run with permissions to write into users directories. You’ve shifted goal posts to now talk about desktop applications when the topic was originally about daemons
        IshKebab 6mo ago
        > You’ve shifted goal posts to now talk about desktop applications when the topic was originally about daemons You imagined that. The topic was never originally about daemons.
        hnlmorg 6mo ago
        It’s literally in the opening post you replied to: > A local privilege escalation to root via an exploitable service? > Doesn't Linux have one of these CVEs...each week? Why else would people be talking about docker, and user/group ownership of running services, and so on and so forth, in response to their comment and yours?
        IshKebab 6mo ago
        If you actually read the article, the "exploitable service" is Windows Defender scanning a file that the user has downloaded.
    - hnlmorg 7mo ago
      How are you going to do that without write access to the users home directory? Like I said before, your RCE exploit will be running as the user and group of the service you exploited. For example www:www So you’re not going to be able to write into Joe Bloggs .bashrc file unless Joe was stupid enough to enable write permission to “other”. Which, once again, requires the user to purposely modify the system into being less secure than its default configuration
      - IshKebab 7mo ago
        > your RCE exploit will be running as the user and group of the service you exploited. For example www:www Only if the exploit is through a web server or similar. If it's through the user's web browser, email client, video player, etc. etc. then you'll have write access to their home directory.
        hnlmorg 7mo ago
        But thats not a daemon then. Thats a completely different type of exploit from the ones we were originally talking about. Yes, if a desktop application has a bug then it can do damage. But at that point, who cares about sudo? The exploit already has access to your ssh keys, browser cookies and history (so can access banking and shopping sites), crypto-currency wallets and so on and so forth. What an exploit has access to here is so much worse than getting root access on a desktop OS.

by hnlmorg 7mo ago

IshKebab 7mo ago

A target user. If you get local code execution on the account of a user that uses sudo you can trivially got root. Doesn't matter if they disabled the password authentication or not.

hnlmorg 7mo ago
Of course it matters if they disabled password authentication. If you require password authentication when running sudo then an attacker has to find a RCE exploit and then crack a password. Which is waaay beyond any effort the average attacker is willing to invest. Because At that point, root access isn’t really worth the effort. An attacker will probably just use the host for sending spam emails, bot / DDoS traffic or look for other daemons they can jump to which weren’t web accessible (eg a database). And furthermore, if you’ve got a RCE in a daemon then that code is the running as the daemons’ user. Which shouldn’t be in the sudoers file (eg wheel group) to begin with.
- IshKebab 7mo ago
  > If you require password authentication when running sudo then an attacker has to find a RCE exploit and then crack a password. Nope! Just alias sudo to something that logs the password.
  - gamer191 7mo ago
    Interesting. If that’s possible (I haven’t tested it, but I’m sure it is) then you wouldn’t even need to log the password. You could just alias sudo to a bash script that runs your malicious payload using the real sudo. Then the user would run the command, be prompted for their password by the real sudo, and be none the wiser that a malicious script has just been executed For what it’s worth, Windows’ security model says it’s not an exploit that programs can grant themselves admin rights if the user is an admin (https://github.com/hfiref0x/UACME https://github.com/hfiref0x/UACME). But afaik Linux doesn’t have that model so it is a bit of an issue that this is possible
    - hnlmorg 7mo ago
      > Interesting. If that’s possible It’s not possible. At least not unless those users have already borked their own system. The previous poster was clutching at straws.
      - IshKebab 7mo ago
        Of course it's possible. I've tried it. It works. It's just standard Unix features. What makes you think it isn't possible?
        hnlmorg 7mo ago
        For the reasons I’ve already stated: daemons don’t run with permissions to write into users directories. You’ve shifted goal posts to now talk about desktop applications when the topic was originally about daemons
        IshKebab 6mo ago
        > You’ve shifted goal posts to now talk about desktop applications when the topic was originally about daemons You imagined that. The topic was never originally about daemons.
        hnlmorg 6mo ago
        It’s literally in the opening post you replied to: > A local privilege escalation to root via an exploitable service? > Doesn't Linux have one of these CVEs...each week? Why else would people be talking about docker, and user/group ownership of running services, and so on and so forth, in response to their comment and yours?
        IshKebab 6mo ago
        If you actually read the article, the "exploitable service" is Windows Defender scanning a file that the user has downloaded.
  - hnlmorg 7mo ago
    How are you going to do that without write access to the users home directory? Like I said before, your RCE exploit will be running as the user and group of the service you exploited. For example www:www So you’re not going to be able to write into Joe Bloggs .bashrc file unless Joe was stupid enough to enable write permission to “other”. Which, once again, requires the user to purposely modify the system into being less secure than its default configuration
    - IshKebab 7mo ago
      > your RCE exploit will be running as the user and group of the service you exploited. For example www:www Only if the exploit is through a web server or similar. If it's through the user's web browser, email client, video player, etc. etc. then you'll have write access to their home directory.
      - hnlmorg 7mo ago
        But thats not a daemon then. Thats a completely different type of exploit from the ones we were originally talking about. Yes, if a desktop application has a bug then it can do damage. But at that point, who cares about sudo? The exploit already has access to your ssh keys, browser cookies and history (so can access banking and shopping sites), crypto-currency wallets and so on and so forth. What an exploit has access to here is so much worse than getting root access on a desktop OS.