Path: utzoo!mnetor!uunet!husc6!think!ames!pasteur!ucbvax!decvax!mandrill!hal!ncoast!allbery From: allbery@ncoast.UUCP (Brandon Allbery) Newsgroups: comp.bugs.sys5 Subject: Re: A security hole Message-ID: <7583@ncoast.UUCP> Date: 3 Apr 88 18:54:55 GMT References: <181@wsccs.UUCP> <722@rivm05.UUCP> <478@minya.UUCP> <7521@ncoast.UUCP> <130@heart-of-gold> Reply-To: allbery@ncoast.UUCP (Brandon Allbery) Followup-To: comp.bugs.sys5 Organization: Cleveland Public Access UN*X, Cleveland, Oh Lines: 28 As quoted from <130@heart-of-gold> by jc@heart-of-gold (John M Chambers x7780 1E342): +--------------- | In article <7521@ncoast.UUCP>, allbery@ncoast.UUCP (Brandon Allbery) writes: | > If I wasn't *real* careful with the (setuid) program which grabs incoming | > sources.misc submissions, someone could gain write access to any of my files. | > Such as my .login. This isn't a potential security hole? (The alternative | > is to make a certain directory world-writeable; not a sound idea in this case.) | | OK, I'll bite. Here are the permissions on my home directory and .login: | | drwxrwxr-x 21 jc wheel 2560 Mar 24 08:30 . | -rw-r--r-- 2 jc wheel 250 Jan 29 14:53 .login | | And here's the rnews command: | | 22531 -rwsr-sr-x 2 news news 114688 Mar 17 13:33 /news/bin/rnews | | Explain to me how someone could use this setuid-news, setgid-news program | to write into my .login file. Now need to explain further; I do appreciate +--------------- -rwsr-xr-x 1 allbery System 56462 Mar 20 16:33 /u/allbery/bin/stash Recall that moderated submissions are *mailed* to the moderator, not posted. And, of course, I should hope that I own my home directory and .login. -- Brandon S. Allbery, moderator of comp.sources.misc {well!hoptoad,uunet!hnsurg3,cbosgd,sun!mandrill}!ncoast!allbery