SetUID\uc640 Permission<\/P>
\n
\uc7a0\uae50 \uc9ec\uc744 \ub0b4\uc11c SetUID \ub77c\ub294 \uac83\uc5d0 \ub300\ud574 \uc9da\uace0 \ub118\uc5b4\uac00\uace0\uc790 \ud569\ub2c8\ub2e4.
SUID\uc5d0 \ub300\ud574\uc11c \uc54c\uae30 \uc704\ud574\uc11c\ub294 \ud37c\ubbf8\uc158(Permission)\uc5d0 \ub300\ud574\uc11c \uc54c\uc544\uc57c \ud558\uc8e0. <\/P>
\n
1. \ud37c\ubbf8\uc158\uc774 \uc65c \uc874\uc7ac\ud558\ub294\uac00?
; \uc720\ub2c9\uc2a4\ub294 \ub3c4\uc2a4\uc640\ub294 \ub2ec\ub9ac \uba40\ud2f0 \uc720\uc838 \uc6b4\uc601\uccb4\uc81c \uc785\ub2c8\ub2e4. \ub9ce\uc740 \uc0ac\ub78c\ub4e4\uc774 \ub3d9\uc2dc\uc5d0 \ud558\ub098\uc758
\uc11c\ubc84\uc5d0\uc11c \uc77c\uc744 \ud560 \uc218\uac00 \uc788\uc8e0. \uc70895\ub098 98, \ub3c4\uc2a4\uac19\uc740 \uc2dc\uc2a4\ud15c\uc5d0\uc11c\ub294 \ud55c\uac1c\uc758 \uc11c\ubc84\ub2f9 \ud55c\uba85\uc758
\uc0ac\ub78c\uc774 \uc0ac\uc6a9\ud560 \uc218 \uac00 \uc788\uc8e0. \uc774\ub807\uac8c \ucef4\ud4e8\ud130 \ud55c\ub300\ub97c \ud55c\uba85\uc774 \uc0ac\uc6a9\ud560 \ub54c\ub294 \ud37c\ubbf8\uc158\uc774\ub77c\ub294
\uac1c\ub150\uc740 \uc804\ud600 \ud544\uc694\uac00 \uc5c6\uc2b5\ub2c8\ub2e4. \ud558\uc9c0\ub9cc \uc5ec\ub7ec\uba85\uc774 \uc0ac\uc6a9\ud558\ub294 \uc720\ub2c9\uc2a4 \ud658\uacbd\uc5d0\uc11c\ub294 \uac01\uac01 \uac1c\uc778\uc744
\uad6c\ubd84 \uc2dc\ucf1c\uc904 \ubb34\uc5b8\uac00\uac00 \ud544\uc694\ud588\uc8e0. \ub098\uc6b0\ub204\ub9ac,\ud558\uc774\ud154,\ucc9c\ub9ac\uc548 \uac19\uc774 \uc544\uc774\ub514\ub85c\uc368 \uc0c1\ub300\ubc29\uc744
\uad6c\ubd84\ud558\ub4ef\uc774\uc694.. \ub9cc\uc57d \ub098\uc6b0\ub204\ub9ac,\ud558\uc774\ud154,\ucc9c\ub9ac\uc548 \uac19\uc740 \ub300\ud615 \ud1b5\uc2e0\ub9dd\uc5d0\uc11c \ubaa8\ub4e0 \uc0ac\ub78c\uc774 \ud558\ub098\uc758
\uc544\uc774\ub514\ub85c \uc9c0\ub0b8\ub2e4\uba74 \uc5c4\uccad \ubd88\ud3b8\ud558\uaca0\uc8e0. \uadf8\ub807\uae30 \ub54c\ubb38\uc5d0 \uac01\uc790\uc758 \uc544\uc774\ub514\uac00 \uc788\uace0 \ub610\ud55c \uc0c1\ub300\ubc29\uc758
\uc601\uc5ed\uc744 \uce68\ubc94\ud558\uc9c0 \ubabb\ud558\uac8c \ud574 \ub193\uc558\uc8e0. \uc0c1\ub300\ubc29\uc758 \ud504\ub77c\uc774\ubc84\uc2dc\ub97c \uce68\ud574\ud558\uc9c0 \uc54a\ub3c4\ub85d\uc694..
\uc720\ub2c9\uc2a4\ub3c4 \ub611\uac19\uc544\uc694. \uac1c\uac1c\uc778\uc758 \uc544\uc774\ub514\uac00 \uc874\uc7ac\ud558\uace0 \uac1c\uac1c\uc778\uc758 \uc544\uc774\ub514\uac00 \ub9cc\ub4e4\uc5b4\ub0b4\ub294 \ud30c\uc77c\uc744
\ub0a8\uc774 \uc77d\uc9c0 \ubabb\ud558\uac8c \ud558\ub824\uba74 \ud37c\ubbf8\uc158\uc774\ub77c\ub294 \uac1c\ub150\uc73c\ub85c \ud30c\uc77c\uc5d0 \ub300\ud55c \ub8f0\uc744 \ud560\ub2f9\ud558\ub294 \uac70\uc8e0.
\ub300\ud615 \ud1b5\uc2e0\ub9dd\uc758 \uc2dc\uc0bd\uacfc\uac19\uc774 \ubaa8\ub4e0 \uac83\uc744 \ud1b5\uc81c\ud560 \uc218 \uc788\ub294 \uad8c\ud55c\uc744 \uac00\uc9c4 \uc0ac\ub78c\uc774 \uc788\ub294 \uac83\ucc98\ub7fc
\uc720\ub2c9\uc2a4\ub3c4 root\ub77c\ub294 \ubaa8\ub4e0 \uac83\uc744 \ud1b5\uc81c\ud560 \uc218 \uc788\ub294 \uad8c\ud55c\uc774 \uc788\ub2f5\ub2c8\ub2e4. <\/P>
\n
2. \ud37c\ubbf8\uc158\uc774\ub780?
; \ud5c8\uac00\ub77c\ub294 \ub73b\uc73c\ub85c \ubcf4\ud1b5 “\uc800 \ud30c\uc77c\uc740 \ud37c\ubbf8\uc158\uc774 \uc5f4\ub824 \uc788\ub2e4” \ub77c\uace0\ud558\ub294\ub370 \uc774 \ub9d0\uc758 \ub73b\uc740 \ud30c\uc77c\uc758
\uc18c\uc720\uad8c\uc790\uac00 \ub2e4\ub978 \uc0ac\ub78c\ub4e4\uc5d0\uac8c\ub3c4 \uc77d\uac70\ub098 \uc4f8\uc218 \uc788\ub3c4\ub85d \ud30c\uc77c\uc5d0 \ub8f0\uc744 \uc815\ud574\uc900 \uac83\uc744 \ub9d0\ud574\uc694.
\ud30c\uc77c\uc5d0 \uc904\uc218 \uc788\ub294 \ub300\ud45c\uc801\uc778 3\uac00\uc9c0 \ub8f0\uc774 \uc788\ub294\ub370 \uadf8\uac83\uc740 r,w,x\ub77c\uace0 \uac04\ub2e8\ud788 \ud45c\uc2dc\ud558\uba70, \ucc28\ub840
\ub300\ub85c \uc77d\uae30, \uc4f0\uae30, \uc2e4\ud589 \uc774\ub7f0 \ub73b\uc774\uc8e0. \uc77c\ubc18\uc801\uc73c\ub85c \uc720\ub2c9\uc2a4\ub294 \ub3c4\uc2a4\uc640\ub294 \ub2ec\ub9ac \ud30c\uc77c\uc774\ub984\uc73c\ub85c
\uc2e4\ud589\ud30c\uc77c\uc774\ub2e4. \uc77d\uae30\uc804\uc6a9 \ud30c\uc77c\uc774\ub2e4 \uc774\ub807\uac8c \uad6c\ubd84\ud558\uc9c0 \uc54a\uc544\uc694. \ub3c4\uc2a4\uc5d0\uc11c\ub294 \ud655\uc7a5\uc790\ub77c\ub294 \uac1c\ub150\uc774
\uc788\uc5b4\uc11c bat,com,exe \ub77c\ub294 \uac83\uc774 \uc2e4\ud589\ud30c\uc77c\uc774\uaca0\uc9c0\ub9cc \uc720\ub2c9\uc2a4\uc5d0\uc11c\ub294 x \ub77c\ub294 \ub8f0\uc774 \uc788\uc744 \uacbd\uc6b0 \uc774
\ud30c\uc77c\uc740 \uc2e4\ud589\uad8c\ud55c\uc744 \uac00\uc84c\ub2e4\uace0 \ub9d0\ud560 \uc218 \uc788\uc8e0. <\/P>
\n
3. \ud37c\ubbf8\uc158\uc758 \uc608..
; \/etc\/passwd \ud30c\uc77c\uc744 \ubcf4\uba74,
$ ls -al \/etc\/passwd
-rw-rwxr– 1 root wheel 1608 Aug 13 09:48 \/etc\/passwd<\/P>
\n
\uc5ec\uae30\uc11c \ub300\ucda9 \ud37c\ubbf8\uc158\uc758 \ubd80\ubd84\uacfc \uc18c\uc720\uad8c \ubd80\ubd84\uc744 \uc54c\uc544\ubd05\uc2dc\ub2e4. \uc5ec\uae30\uc11c root wheel \ub77c\uace0 \ub418\uc5b4\uc788\ub294
\ubd80\ubd84\uc740 \/etc\/passwd \ud30c\uc77c\uc758 \uc18c\uc720\uad8c\uc774 \ub204\uad6c\uc774\uace0 \uadf8\ub8f9\uc774 \ub204\uad6c\uc778\uc9c0\ub97c \uc54c\ub824\uc90d\ub2c8\ub2e4. \uc5ec\uae30\uc11c\ub294
root \uc18c\uc720\uad8c\uc774\uba70, wheel \uc774\ub77c\ub294 \uadf8\ub8f9\uc73c\ub85c \ub418\uc5b4\uc788\uad70\uc694. \ucc38\uace0\ub85c \uc720\ub2c9\uc2a4\uc5d0\uc11c\ub294 \uac01 \uac1c\uc778\uc744 \ub098\ud0c0
\ub0b4\ub294 ID \uc640 \uadf8\ub8f9\uc774\ub77c\ub294 \uac1c\ub150\uc774 \uc874\uc7ac\ud569\ub2c8\ub2e4. \uac1c\uc778 id \uc57c \ubc1c\uae09\ud574\uc11c \ubc1b\ub294 \uac83\uc774\uba70, \uadf8\ub8f9\uc774\ub77c\ub294
\uac1c\ub150\uc740 \uadf8 \ube44\uc2b7\ud55c \uc0ac\ub78c\ub4e4 \ub07c\ub9ac \ubb36\uc5b4 \ub193\ub294 \uac83\uc774\uc5d0\uc694. \uadf8\ub8f9\uc740 \uc774\ub7f4\ub54c \uc544\uc8fc \uc720\uc6a9\ud558\uc8e0.. <\/P>
\n
\uadf8 \ub2e4\uc74c, -rw-rwxr– \uc774\ub77c\uace0 \ub418\uc5b4\uc788\uc8e0? \uc55e\uc758 – \ub294 \ud30c\uc77c\uc778\uc9c0,\ub514\ub809\ud1a0\ub9ac\uc778\uc9c0,\ub514\ubc14\uc774\uc2a4 \ud30c\uc77c
\uc778\uc9c0\ub97c \uad6c\ubd84, rw- , r– , r– \uc774\ub807\uac8c \ub418\uc5b4\uc788\ub294\ub370 \uc55e\uc758 \ub2e8\uc740 \ud30c\uc77c\uc740 \ub9cc\ub4e0\uc0ac\ub78c \uc989, \uc18c\uc720\uc790\uc5d0
\ub300\ud55c \ud37c\ubbf8\uc158(rw:\uc77d\uace0,\uc4f0\uae30\uac00\ub2a5), \ub450\ubc88\uc9f8 \ub2e8\uc758 rwx \uc740 \ud30c\uc77c\uc758 \uadf8\ub8f9\uc18c\uc720\uad8c\uc5d0\ub300\ud55c \ud37c\ubbf8\uc158(rwx :
\uc77d\uae30,\uc4f0\uae30,\uc2e4\ud589 \uac00\ub2a5) \uc138\ubc88\uc9f8 \ub2e8\uc740 r– \uc740 \uc2dc\uc2a4\ud15c \ub0b4\uc758 \ubaa8\ub4e0 \uc0ac\uc6a9\uc790\uc5d0 \ub300\ud55c \ud37c\ubbf8\uc158
(r–:\uc77d\uae30\ub9cc \uac00\ub2a5)\uc744 \ub098\ud0c0\ub0b4\ub294 \uac70\uc8e0. <\/P>
\n
\uc790 \uadf8\ub7fc \uc774\uac83\uc744 \uc885\ud569\ud558\uc790\uba74 \/etc\/passwd \ud30c\uc77c\uc758 \uc18c\uc720\uc790\ub294 root \uc774\uace0 \uadf8\ub8f9\uc18c\uc720\uc790\ub294 root \uc774\ub78d\ub2c8\ub2e4.
\uadf8\ub9ac\uace0 \ud37c\ubbf8\uc158\uc740 \ubaa8\ub4e0 \uc0ac\uc6a9\uc790\uc5d0\uac8c\ub294 \uc77d\uae30\ub9cc\uc744 \ud5c8\uc6a9\ud558\uace0, \uac19\uc740 \uadf8\ub8f9 \uc0ac\uc6a9\uc790\ub4e4\uc5d0\uac8c\ub294 \uc77d\uae30,\uc4f0\uae30,
\uc2e4\ud589\uc774 \uac00\ub2a5\ud558\uba70, \ud30c\uc77c \uc18c\uc720\uc790\uc778 root\uc5d0\uac8c\ub294 \uc77d\uae30\uc4f0\uae30\uac00 \uac00\ub2a5\ud558\ub2f5\ub2c8\ub2e4.
\uc774\uc81c \uc774\ud574\uac00 \uac00\uc2dc\ub098\uc694? <\/P>
\n
(\uc608\uc81c)
$ ls -al \/etc\/shadow
-r——– 1 root root 1736 Aug 12 10:41 \/etc\/shadow \uc774\uac83\uc758 \uc815\ubcf4\ub294 \uc5b4\ub5a4\uac00\uc694?
\/etc\/shadow \ud30c\uc77c\uc758 \uc815\ubcf4\ub97c \ubcf4\uc5ec\uc900 \uac83\uc73c\ub85c \uc18c\uc720\uad8c\uc740 root \uc774\uba70, \uadf8\ub8f9 \uc18c\uc720\uad8c\uc740 root\uc774\uba70,
\ubaa8\ub4e0 \uc0ac\uc6a9\uc790\uc5d0\uac8c\ub294 \ud37c\ubbf8\uc158\uc774 \ub2eb\ud600\uc788\uc8e0? \uadf8\ub9ac\uace0 \uc624\ub85c\uc9c1 root \uc5d0\uac8c\ub9cc \uc77d\uae30 \uad8c\ud55c \ud558\ub098\ub9cc \uc5f4\ub824
\uc788\ub2f5\ub2c8\ub2e4. \/etc\/shadow \ud30c\uc77c\uc740 \ubc14\ub85c \uacc4\uc815\uc774\uc6a9\uc790\uc758 \ube44\ubc00\ubc88\ud638\uac00 \ub2f4\uaca8\uc838 \uc788\uc5b4\uc11c \uadf8\ub807\ub2f5\ub2c8\ub2e4. <\/P>
\n
4. SetUID \ub780?
SetUID \ub77c\ub294 \ub294 \uac83\uc740 \uc784\uc2dc\uc801\uc73c\ub85c \uc0ac\uc6a9\uc790\uc758 \uad8c\ud55c\uc744 \ubc14\uafd4\uc904\uc218 \uc788\ub294 \ub8f0\uc744 \ud30c\uc77c\uc5d0 \uc801\uc6a9\uc2dc\ucf1c\uc8fc\ub294
\uac83\uc744 \ub9d0\ud574\uc694. \uc77c\ubc18 \uacc4\uc815 \uc774\uc6a9\uc790\uac00 \uc5b4\ub5a4 \ud504\ub85c\uadf8\ub7a8\uc744 \uc774\uc6a9\ud574\uc57c \ud558\ub294\ub370 \uc774 \ud504\ub85c\uadf8\ub7a8\uc740 root
\ub9cc\uc774 \uc0ac\uc6a9\uc774 \uac00\ub2a5\ud558\uac8c \ub9cc\ub4e4\uc5b4\uc838 \uc788\ub2f5\ub2c8\ub2e4. \uadf8\ub807\ub2e4\uba74 \uc77c\ubc18 \uacc4\uc815 \uc774\uc6a9\uc790\uac00 \uadf8 \ud504\ub85c\uadf8\ub7a8\uc744
\ub3cc\ub9ac\ub824\uba74 \ub8e8\ud2b8\uac00 \ub418\uc57c\uaca0\uc8e0? \ud558\uc9c0\ub9cc \uc544\ubb34\uc5d0\uac8c\ub098 \ub8e8\ud2b8\ub97c \uc904 \uc218 \uc5c6\ub294 \ubc95…..
\uacb0\ub860\uc740 \uadf8 \ud504\ub85c\uadf8\ub7a8\uc774 \ub3cc\ub54c\ub9cc \uc7a0\uc2dc \ub8e8\ud2b8\ub85c \ub418\uac8c \ud558\uace0 \ud504\ub85c\uadf8\ub7a8\uc774 \ub05d\ub098\uba74 \uc6d0\ub798 \uacc4\uc815id\ub85c
\ub3cc\uc544\uc640\uc57c\uaca0\uc8e0. \uc774\ub7f4\ub54c \ubc14\ub85c SetUID \ub77c\ub294 \uac1c\ub150\uc774 \ud544\uc694\ud55c \uac83\uc774 \uc544\ub2d0\uae4c\uc694? \uc880\ub354 \uad6c\uccb4\uc801\uc73c\ub85c
\uc608\ub97c \ub4e4\uc5b4\ubcfc\uae4c\uc694? \ubcf4\ud1b5 password \ub97c \ubc14\uafb8\ub824\uba74 \uc720\ub2c9\uc2a4\uc5d0\uc11c \uc5b4\ub5a4 \uba85\ub839\uc744 \ub0b4\ub9b4\uae4c\uc694?
$ passwd
Changing password for user bugscan
New UNIX password:
Retype new UNIX password:
\uc774\ub7f0\uc2dd\uc73c\ub85c \ubc14\uafb8\uc8e0? \uadf8\ub807\ub2e4\uba74 \uadf8 \ubc14\ub010 \ud328\uc2a4\uc6cc\ub4dc\ub294 \uc5b4\ub514\uc5d0 \uc800\uc7a5\ub420\uae4c\uc694? \ubc14\ub85c..
\/etc\/shadow \ub77c\ub294 \ud30c\uc77c\uc774\uc8e0. \uc544~~ \uae30\uc5b5\ub098\uc138\uc694? \/etc\/shadow \ub77c\ub294 \ud30c\uc77c\uc740 -r——– \uc73c\ub85c
\ud37c\ubbf8\uc158\uc774 \uc124\uc815\ub418\uc5b4\uc788\uc5b4\uc694. \uc800\uae30 \uc704\ub97c \ubcf4\uc2dc\uae38.. \uc774\uac83\uc740 \uc77c\ubc18 \uc0ac\uc6a9\uc790\ub85c\uc368\ub294 \uc811\uadfc\uc774 \ubd88\uac00\ub2a5
\ud558\uc8e0. \uc624\ub85c\uc9c0 \uc18c\uc720\uad8c\uc774 root\ub9cc\uc774 \uc77d\uae30\ub9cc \uac00\ub2a5\ud574\uc694. \uadf8\ub807\ub2e4\uba74 \uc6b0\ub9ac\uc758 \uc77c\ubc18 \uacc4\uc815\uc73c\ub85c \ub3cc\ub9b0
\ud504\ub85c\uadf8\ub7a8\uc774 \uc5b4\ub5bb\uac8c \ud37c\ubbf8\uc158\uc774 \ub2eb\ud600 \uc788\ub294 \/etc\/shadow \ud30c\uc77c\uc5d0 \ubc14\ub010 \uc554\ud638\ub97c \uc800\uc7a5\ud560 \uc218 \uc788\uc744
\uae4c\uc694? \uc774\ub7f0 \uc758\ubb38\uc774 \uc788\ub294 \uc0ac\ub78c\ub3c4 \uc788\uc744\uaebc\uc5d0\uc694. \uadf8\ub0e5 passwd \ub77c\ub294 \ud504\ub85c\uadf8\ub7a8\uc774 \/etc\/shadow
\ud30c\uc77c\uc744 \ubc14\uafb8\uc9c0 \uc54a\uc544\uc694? \ud558\uc9c0\ub9cc \ud504\ub85c\uadf8\ub7a8\uc744 \uc2e4\ud589\uc2dc\ud0ac\ub54c \uc544\ubb34\ub9ac \ud504\ub85c\uadf8\ub7a8\uc774 \uad49\uc7a5\ud574\ub3c4 \uc2e4\ud589
\uc2dc\ud0a8 \uc0ac\ub78c\uc758 \uad8c\ud55c \uc774\uc0c1\uc758 \uc77c\uc744 \ubabb\ud55c\ub2f5\ub2c8\ub2e4. \uadf8\uac8c \uaddc\uce59\uc774\uc8e0. \uc774\uc81c suid \uac1c\ub150\uc774 \ub098\uc640\uc57c \ud558\uaca0
\ub124\uc694. suid\ub294 \ud30c\uc77c\uc758 \uc18c\uc720\uc790 \ud639\uc740 root \uc0ac\uc6a9\uc790\ub9cc \uc124\uc815\ud560 \uc218 \uc788\uc5b4\uc694. chmod \ub77c\ub294 \ud37c\ubbf8\uc158\uc744
\uc124\uc815\ud558\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc774\uc6a9\ud558\uc8e0.
-rwsr-xr-x 1 level1 level0 12900 Jul 27 15:00 \/aa
\uc774\ub7f0 \uacbd\uc6b0\uac00 \ubc14\ub85c suid \uac00 \uac78\ub824 \uc788\ub294 \uacbd\uc6b0\ub78d\ub2c8\ub2e4. \ud37c\ubbf8\uc158\uc774 \uc124\uc815\ub41c \ubd80\ubd84\uc744 \ubcf4\uc138\uc694. \uc77c\ubc18\uc801
\uc73c\ub85c \ud37c\ubbf8\uc158 \uc124\uc815\uc740 rwx\uc774\ub7f0 \uc2dd\uc73c\ub85c \ub418\uc5b4\uc788\ub294\ub370 x \ub300\uc2e0 s \ub77c\ub294 \uac83\uc774 \uc788\uc8e0. \uc774\ub54c\uac00 \ubc14\ub85c
\uc18c\uc720\uad8c\uc5d0 suid \uac00 \uac78\ub824 \uc788\uc5b4\uc694. \uc5b4\ub5a4 \uc0ac\uc6a9\uc790\ub77c\ub3c4 \/aa \ub77c\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc2e4\ud589\ud558\uba74 \uadf8 \uc2e4\ud589\ub418\ub294
\uc21c\uac04 \ub9cc\ud07c\uc740 level1 \uc774\ub77c\ub294 \ud30c\uc77c \uc18c\uc720\uad8c\uc758 \uad8c\ud55c\uc744 \uac00\uc9c0\uac8c \ub418\ub294 \uac70\uc8e0. \ud504\ub85c\uadf8\ub7a8\uc774 \uc885\ub8cc\ub418\uba74
\ub2e4\uc2dc \uc6d0\ub798 \uc790\uc2e0\uc758 \uad8c\ud55c\uc73c\ub85c \ub3cc\uc544\uc640\uc694. \uc774\ub7f0 \uac83\ub4e4\uc774 \ubc14\ub85c suid \uc124\uc815\uc774\ub78d\ub2c8\ub2e4. \uae38\uac8c\ub294 SetUID
\ub77c\uace0\ub3c4 \ud558\uba70 \uc904\uc5ec\uc11c suid \ub77c\uace0 \ud558\uc8e0. <\/P>
\n
5. SetUID\uc758 \uc704\ud5d8\uc131
\uc7a0\uc2dc setuid \ub77c\ub294 \uac83\uc744 \uc9da\uace0 \ub118\uc5b4\uac00\uc790\uba74 \ud30c\uc77c\uc5d0 \uc124\uc815\ub418\ub294 \ub8f0\uc911\uc5d0 \ud558\ub098\ub85c \uc5b4\ub5a4 \uc0ac\ub78c\uc774\ub4e0 \uadf8
\ub8f0\uc774 \uc124\uc815\ub41c \ud30c\uc77c\uc744 \uc2e4\ud589\ud558\uba74 \uadf8 \ud30c\uc77c\uc758 \uc18c\uc720\uad8c\uc758 \uacc4\uc815(ID)\uc73c\ub85c \uadf8 \ud504\ub85c\uadf8\ub7a8\uc774 \ub3cc\uac8c \ub418\uc8e0.
\ud639\uc2dc cat \uc774\ub77c\ub294 \uba85\ub839\uc744 \uc544\uc2dc\ub098\uc694? \uc774 \ud504\ub85c\uadf8\ub7a8\uc740 \ud30c\uc77c\uc744 \uc77d\uac70\ub098, \uc4f8\uc218 \uc788\ub294 \uae30\ub2a5\uc744 \uac00\uc9c0\uace0 \uc788\uc8e0.
\uc608\ub97c \ub4e4\uba74, $ cat \/etc\/passwd \ub77c\uace0 \ud558\uba74 \/etc\/passwd \ud30c\uc77c\uc744 \uc77d\uc8e0. \ub9cc\uc57d bugscan \uc774\ub77c\ub294
\uc0ac\ub78c\uc774 \ub9cc\ub4e0 \ud30c\uc77c\uc774 \uc788\ub294\ub370 \ud37c\ubbf8\uc158\uc774 \uc77c\ubc18 \uc0ac\uc6a9\uc790\ub4e4 \ud55c\ud14c\ub294 \ub2eb\ud600 \uc788\ub2e4\uace0 \ud569\uc2dc\ub2e4.
\uc989, \uc774\ub7f0 \uc2dd\uc73c\ub85c \ud37c\ubbf8\uc158\uc774 \uc124\uc815\ub418\uc5b4\uc788\ub2e4\uace0 \ubcf4\uba74 \ub420\uaebc\uc5d0\uc694..<\/P>
\n
-rw——- 1 bugscan admin 45147 8\uc6d4 19\uc77c 15:45 \/tmp\/passwd
(\uc138\ubc88\uc9f8 \ub2e8\uc774 — \uc73c\ub85c \ub418\uc5b4\uc788\uc73c\ubbc0\ub85c \uc77c\ubc18 \uc0ac\uc6a9\uc790\ub4e4\ud55c\ud14c\ub294 \ud37c\ubbf8\uc158\uc774 \ub2eb\ud600 \uc788\uc5b4\uc11c \uc77d\uc9c0\ub3c4 \uc2e4\ud589
\ud558\uc9c0\ub3c4 \uc4f0\uc9c0\ub3c4 \ubabb\ud55c\ub2e4. \uc624\ub85c\uc9c0 \ud30c\uc77c \uc18c\uc720\uc790\ub9cc\uc774 \uc77d\uace0 \uc4f8\uc218 \uc788\ub2e4.)<\/P>
\n
$ whoami
guest
$ ls -al \/tmp\/passwd
-rw——- 1 bugscan admin 45147 8\uc6d4 19\uc77c 15:45 \/tmp\/passwd
$ ls -al \/bin\/cat
-r-xr-xr-x 1 bin bin 9388 Jul 16 1997 \/bin\/cat
$ cat \/tmp\/passwd
cat: cannot open \/tmp\/passwd <\/P>
\n
\ubcf4\ub2e4 \uc2dc\ud53c \/tmp\/passwd \ud30c\uc77c\uc740 \uc788\uc9c0\ub9cc cat \uc73c\ub85c \ud30c\uc77c\uc744 \uc5f4\uc218 \uc5c6\ub2e4\uace0 \ub098\uc624\uc8e0? \ubc14\ub85c guest \uc640 \uac19\uc740
bugscan \uacfc \ub2e4\ub978 \uc544\uc774\ub514\uc758 \uc0ac\uc6a9\uc790 \uc5d0\uac8c\ub294 \ud37c\ubbf8\uc158\uc744 \uc5f4\uc9c0 \uc54a\uc544\uc11c \uaca0\uc8e0.<\/P>
\n
\uc790 \ud55c\ubc88 \uc774\ubc88\uc5d0\ub294 \uc774\ub7f0 \uc2dd\uc73c\ub85c \ub418\uc5b4\uc788\uc744 \uacbd\uc6b0 \/tmp\/passwd \ud30c\uc77c\uc744 \uc77d\uc744 \uc218 \uc788\uc8e0.<\/P>
\n
$ whoami
guest
$ ls -al \/tmp\/passwd
-rw——- 1 bugscan admin 45147 8\uc6d4 19\uc77c 15:45 \/tmp\/passwd
$ ls -al \/bin\/cat
-r-sr-xr-x 1 bugscan bin 9388 Jul 16 1997 \/bin\/cat
$ cat \/tmp\/passwd
\uc5b4\uca4c\uad6c \uc800\uca4c\uad6c. \ud328\uc2a4\uc6cc\ub4dc\uac00 \uc5ec\uae30\uc788\uace0, \uc800\uae30\uc788\uace0.. \uc5ec\uae30\ub3c4 \uc788\uc5c8\uad70. \uc774\uc81c \uc5c6\ub098\ubcf4\ub2e4.. <\/P>
\n
\uc9c0\uae08\uc740 \/tmp\/passwd \ud30c\uc77c\uc744 \uc77d\uc744 \uc218 \uc788\uc8e0.. \uc65c \uadf8\ub7f4\uae4c\uc694?
\uadf8 \ud574\ub2f5\uc740 \ubc14\ub85c \/bin\/cat \ub77c\ub294 \ud30c\uc77c\uc758 \ud37c\ubbf8\uc158\uc744 \ubcf4\uc2dc\uba74 \ub420\uaebc\uc5d0\uc694.
cat \uc758 \uc18c\uc720\uad8c\uc740 bugscan \uc774\uace0 setuid \uac00 \uac78\ub824 \uc788\uc8e0.
\uc989, \ud604\uc7ac\uc758 guest \uc0ac\uc6a9\uc790\ub294 cat \uc774\ub77c\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \ub3cc\ub9ac\ub294 \uc21c\uac04\ub9cc\ud07c\uc740 bugscan \uc774\ub77c\ub294 \uc544\uc774\ub514\ub85c
\ub3cc\uc544\uac04\uac83\uc774\uc8e0.. \uadf8\ub807\uae30 \ub54c\ubb38\uc5d0 \ud37c\ubbf8\uc158\uc774 \ub2eb\ud600\uc9c4 \/tmp\/passwd \ud30c\uc77c\uc744 \uc77d\uc744 \uc218 \uc788\ub294 \uac83\uc774\uace0\uc694.. <\/P>
\n
\uadf8\ub7fc \uc774\ubc88\uc5d0\ub294 cat \ud504\ub85c\uadf8\ub7a8\uc774 \uc544\ub2cc \/bin\/more \ub77c\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc0b4\ud3b4\ubd05\uc2dc\ub2e4.
more \ub77c\ub294 \ud504\ub85c\uadf8\ub7a8\ub3c4 cat\uacfc \uac19\uc774 \ud30c\uc77c\uc744 \uc77d\uc744 \uc218 \uc788\ub294 \uae30\ub2a5\uc744 \uac00\uc9c0\uace0 \uc788\uc2b5\ub2c8\ub2e4.
\ud558\uc9c0\ub9cc cat \uba85\ub839\uacfc \ub2e4\ub978 \uc810\uc740 \ud55c\ud398\uc774\uc9c0\uac00 \ub118\ub294 \ubb38\uc11c \ud30c\uc77c\uc77c \uacbd\uc6b0 \uc544\ubb34\ud0a4\ub098
\ub204\ub974\ub3c4\ub85d\ud558\uace0 \ud654\uba74\uc744 \uc815\uc9c0 \uc2dc\ud0b5\ub2c8\ub2e4.
\ub3c4\uc2a4\uc758 dir \/p \uba85\ub839\uacfc \uac19\uc774 p \uc635\uc158\uc744 \uc918\uc11c \ud654\uba74\uc744 \uba48\ucd94\uac8c \ud558\ub294 \uac70\uc8e0.
cat \ub300\uc2e0 more \ub77c\ub294 \ud30c\uc77c\uc5d0 setuid \ub97c \uc8fc\uace0 \ub2e4\uc2dc \ud55c\ubc88 \/tmp\/passwd \ud30c\uc77c\uc744 \ubd05\uc2dc\ub2e4. <\/P>
\n
$ whoami
guest
$ ls -al \/tmp\/passwd
-rw——- 1 bugscan admin 45147 8\uc6d4 19\uc77c 15:45 \/tmp\/passwd
$ ls -al \/bin\/cat
-r-sr-xr-x 1 bugscan bin 21418 Jul 16 1997 \/bin\/more
$ more \/tmp\/passwd
\uc5b4\uca4c\uad6c \uc800\uca4c\uad6c.
\ud328\uc2a4\uc6cc\ub4dc\uac00 \uc5ec\uae30\uc788\uace0, \uc800\uae30\uc788\uace0..
\uc5ec\uae30\ub3c4 \uc788\uc5c8\uad70. \uc774\uc81c \uc5c6\ub098\ubcf4\ub2e4..
….
….
….
–More–(2%) <\/P>
\n
\uc544\uae4c cat \uba85\ub839\uc744 \ub0b4\ub838\uc744 \ub54c \uc640 \ubcc4 \ub2e4\ub978\uac70 \uc5c6\uc8e0? \ub2e4\ub9cc –More–(2%) \ub77c\ub294 \uac83\uc774 \ub098\uc640\uc11c \ud398\uc774\uc9c0
\ubcc4\ub85c \ub0b4\uc6a9\uc744 \ubcfc\uc218 \uc788\uc744\ubfd0.. \ud558\uc9c0\ub9cc more \uc758 \ub0b4\ubd80 \uba85\ub839\uc911 \uc774\ub7f0 \uac83\uc774 \uc788\uc8e0.. ! \ub77c\ub294 \uba85\ub839\uc774 \ud575\uc2ec\uc785\ub2c8\ub2e4.
! (\ub290\ub08c\ud45c) \uba85\ub839\uc740 \uadf8 \ub4a4\uc5d0 \ubd99\uc778 \ud30c\uc77c\uc774\ub984\uc744 \uc2e4\ud589\ud558\ub77c\ub294 \uba85\ub839\uacfc \uac19\uc544\uc694.
\uc989 \uc774\ub807\uac8c \uba85\ub839\uc744 \ub0b4\ub9b4\uc218\uac00 \uc788\uc8e0.
!cat \/tmp\/passwd \ub77c\uace0 \uba85\ub839\uc744 \ub0b4\ub9ac\uba74 \ud604\uc7ac\uc758 \uad8c\ud55c\uc73c\ub85c cat \/tmp\/passwd \uba85\ub839\uc744 \ub0b4\ub9ac\uc8e0. <\/P>
\n
\uc544!!! \uc7a0\uae50 \uc5ec\uae30\uc11c..<\/P>
\n
\ud604\uc7ac\uc758 \uad8c\ud55c\uc73c\ub85c cat \/tmp\/passwd \uba85\ub839\uc744 \ub0b4\ub9b0\ub2e4\uace0 \ud588\uc8e0?
\ud55c\uac00\uc9c0 \uac04\uacfc\ud558\uace0 \ub118\uc5b4\uac04 \ubd80\ubd84\uc740 \ubc14\ub85c suid \uac00 \uac78\ub9b0 \ud504\ub85c\uadf8\ub7a8\uc744 \uc2e4\ud589\uc2dc\ud0a4\ub294 \uc21c\uac04\uc740 \ud30c\uc77c\uc758 \uc18c\uc720\uc790
\uad8c\ud55c\uc774\ub77c\uace0 \ud588\uc8e0? \uadf8\ub807\ub2e4\uba74 \ud504\ub85c\uadf8\ub7a8\uc758 \uc885\ub8cc\uac00 \uc544\ub2cc \uc911\uac04\uc5d0 ! \uba85\ub839\uc73c\ub85c \uc784\uc2dc \uba85\ub839\uc744 \ub0b4\ub9ac\ub294 \uc21c\uac04\uc5d0\ub3c4
setuid\ub294 \uc720\ud6a8\ud558\ub2e4 \uc774\ub9d0\uc774\uc8e0. \uacb0\uad6d \uc911\uac04\uc5d0 !cat \/tmp\/passwd \ub77c\uace0 \ud574\ub3c4 \/tmp\/passwd \ud30c\uc77c\uc740 \ubcf4\uc778\ub2e4\ub294
\uac70\uc8e0. \uc774\uc81c \uc880 \ub208\uce58\uac00 \uc0dd\uae30\ub098\uc694?<\/P>
\n
6. \/bin\/sh \ub77c\ub294 \ud30c\uc77c\uc740 \ubb50\ud558\ub294 \uac74\uac00?
\/bin\/sh \ub77c\ub294 \uac83\uc740 \uc544\uc8fc \uc5ec\ub7ec\ubd84\uc774 \uc2e4\ud589\uc2dc\ud0a4\uace0, \ubb34\uc758\uc2dd\uc801\uc73c\ub85c \ub118\uc5b4\uac00\ub294 \ubd80\ubd84\uc774\uc8e0.
\/etc\/passwd \ud30c\uc77c\uc744 \ud55c\ubc88 \uc0b4\ud3b4\ubcf4\uc138\uc694.<\/P>
\n
% cat \/etc\/passwd
proto40M:x:9683:200:Quota Proto 40M:\/tmp:\/bin\/sh
proto30M:x:9684:200:Quota Proto 30M:\/tmp:\/bin\/sh
proto20M:x:9685:200:Quota Proto 20M:\/tmp:\/bin\/sh
proto10M:x:9686:200:Quota Proto 10M:\/tmp:\/bin\/sh
proto3M:x:8000:200:Quota Proto 3M:\/tmp:\/bin\/sh
proto50M:x:9687:200:Quota Proto 50M:\/tmp:\/bin\/sh
proto70M:x:7833:200:Quota Proto 70M:\/tmp:\/bin\/sh
…. <\/P>
\n
\ub9e8 \ub05d\ubd80\ubd84\uc5d0 \/bin\/sh \ub77c\uace0 \ub418\uc5b4\uc788\uc9c0 \uc54a\uc740\uac00? \ud55c\ubc88 \uac01 \uc11c\ubc84\uc758 \/etc\/passwd \ud30c\uc77c\uc744 \uc77d\uc5b4\ubcf4\uae30 \ubc14\ub798\uc694.<\/P>
\n
\/bin\/sh(\uc258:SHELL) \ud30c\uc77c\uc758 \uc4f0\uc784\uc740 \ud754\ud788 \uc0ac\uc6a9\ud558\ub294 \ub3c4\uc2a4\uc758 command.com \ud30c\uc77c\uacfc \uac19\ub2e4\uace0 \uc0dd\uac01\ud558\uc138\uc694.
“\uba85\ub839\uc5b4 \ud574\uc11d\uae30” \ub77c\uace0\ub3c4 \ubd80\ub974\uc8e0.
\uc6b0\ub9ac\uac00 \uc77c\ubc18\uc801\uc778 \uc720\ub2c9\uc2a4 \ub85c\uadf8\uc778\uc744 \ud558\uac8c \ub418\uba74 \/etc\/passwd \ud30c\uc77c\uc758 \ub9c8\uc9c0\ub9c9\uc5d0 \ubd99\uc5b4\uc788\ub294 \/bin\/sh \uac00 \uc2e4\ud589
\ub418\uba74\uc11c prompt\uac00 \ub728\uac8c \ub418\uc8e0. $ \ud639\uc740 # \uc774\ub7f0\uc2dd\uc73c\ub85c\uc694. \ubc14\ub85c \uc258\uc774 \uc2e4\ud589\ub41c\uac83\uc744 \ub73b\ud558\uc8e0..
\uc258\uc774 \ub728\uba74 \uadf8\ub54c\ubd80\ud130 \uc720\ub2c9\uc2a4\uc758 \ubaa8\ub4e0 \uba85\ub839\uc744 \ub0b4\ub9b4\uc218\uac00 \uc788\ub294 \uac70\uc5d0\uc694..
\/bin\/sh \ud30c\uc77c\uc5d0 \uc190\uc0c1\uc774 \uac00\uac70\ub098 \uc0ad\uc81c\ub418\uba74 \ub85c\uadf8\uc778\uc744 \ubabb\ud558\uac8c \ub418\ub294 \uacb0\uacfc\ub97c \ub0b3\uac8c \ub418\uc8e0.<\/P>
\n
\uadf8\ub807\ub2e4\uba74 \uc774\ub7f0 \uc2dd\uc758 \ud589\ub3d9\uc740 \uc5b4\ub5a4 \uacb0\uacfc\ub97c \ubd80\ub97c\uae4c\uc694?<\/P>
\n
more \ub97c \uc0ac\uc6a9\ud558\ub294 \uacfc\uc815\uc5d0\uc11c !\/bin\/sh \ub77c\uace0 \uce58\uac8c \ub418\uba74 \uc5b4\ub5bb\uac8c \ub418\ub098\uc694? \uc258\uc744 \uc2e4\ud589\ud588\uc73c\ub2c8 $ \ud654\uba74\uc774
\ub098\uc624\uaca0\uc8e0? \ub610\ud55c \ud604\uc7ac \uc2e4\ud589\ub418\ub294 suid \ub294 \uc720\ud6a8\ud560\ud14c\uace0… \uadf8\ub807\ub2e4\uba74 whoami \ub97c \uc774\uc0c1\ud0dc\uc5d0\uc11c \uce58\uba74 bugscan
\uc774\ub77c\uace0 \ub098\uc624\uc9c0 \uc54a\uc744\uae4c\uc694? \ub0b4\ub9ac\ub294 \uba85\ub839\ub9c8\ub2e4 bugscan \uc73c\ub85c \uc2e4\ud589\ud560 \uc218 \uc788\uaca0\uc8e0.. \uc65c\ub0d0… setuid\ub294 \uc544\uc9c1
\uae4c\uc9c0\ub3c4 \uc720\ud6a8\ud558\uae30 \ub54c\ubb38\uc774\uc8e0.. \uc544\uc9c1 more \ud504\ub85c\uadf8\ub7a8\uc740 \uc885\ub8cc\ub41c\uac8c \uc544\ub2c8\ub77c more \uc758 ! \ub77c\ub294 \ub0b4\ubd80 \uba85\ub839\uc5b4 \uc548\uc5d0
\uc788\ub294 \uac83\uc774\uae30 \ub54c\ubb38\uc774\uc8e0.<\/P>
\n
\ub2e4\uc74c\uc740 \ub2f9\uc2e0\uc774 \uacc4\uc815\uc5d0 \uc811\uc18d\ud55c\ud6c4 more \ub97c \uc2e4\ud589\ud574 !\ub85c \uc258\ub85c \ube60\uc9c4 \uacbd\uc6b0\ub97c \ubcf4\uc5ec\uc90d\ub2c8\ub2e4.
login -> \/bin\/sh -> more -> ! -> \/bin\/sh -> ls , cat, vi, telnet , ftp .. \ub4f1\ub4f1<\/P>
\n
7. \ub8e8\ud2b8\uc258(RootShell)
; setuid \uac00 root \ub85c \ub418\uc5b4\uc788\ub294 \uc258\uc744 \ub9d0\ud569\ub2c8\ub2e4.
setuid\ub294 \ubb34\uc5c7\uc778\uc9c0 \uc544\uc2dc\uaca0\uc8e0?
\uc2e4\ud589\ud560 \ud30c\uc77c\uc774 \/bin\/sh \uc774\uace0 \uadf8 \uc18c\uc720\uad8c\uc774 root \uc778 \uacbd\uc6b0 \uc5b4\ub5a4 \ubaa8\uc2b5\uc77c\uae4c\uc694?<\/P>
\n
-r-sr-xr-x 3 root 88620 Jul 16 1997 \/bin\/sh<\/P>
\n
\ubc14\ub85c \uc774\ub7f0 \ubaa8\uc2b5\uc774\uaca0\uc8e0?<\/P>
\n
\uc77c\ubc18\uc801\uc778 \uc815\uc0c1\uc801\uc778 \/bin\/sh\ub294 \uc774\ub807\uc2b5\ub2c8\ub2e4.<\/P>
\n
-r-xr-xr-x 3 root 88620 Jul 16 1997 \/bin\/sh<\/P>
\n
\ub9e8\uc704\uc758 \/bin\/sh\ub97c \uc2e4\ud589\ud558\ub294 \uc21c\uac04 \uc6b0\ub9ac\ub294 setuid \uac00 \uac78\ub824 \uc788\uae30\ub54c\ubb38\uc5d0 root\uac00
\ub418\ub294 \uac70\uc8e0.
\uc258 \uc790\uccb4\ub97c \ub8e8\ud2b8\ub85c \uc2e4\ud589\ud558\ub294 \uac70\ub78d\ub2c8\ub2e4.
\ub2e4\uc74c\uc758 \uc608\uc81c\ub97c \ubcf4\uc138\uc694.<\/P>
\n
$ whoami
guest
$ ls -al \/bin\/sh
-r-sr-xr-x 3 root 88620 Jul 16 1997 \/bin\/sh
$ \/bin\/sh
# whoami
root
# exit
$ whoami
guest<\/P>
\n
\uc774\uc81c \uc544\uc2dc\uaca0\uc8e0?
\uc258 \uc790\uccb4\uac00 \uc885\ub8cc\ub420\ub54c\uae4c\uc9c0\ub294 setuid \uac00 \uc720\ud6a8 \ud558\ub2f5\ub2c8\ub2e4.<\/P>
\n
8. \ud37c\ubbf8\uc158 \uc124\uc815 \ubc29\ubc95
\uc6b0\uc120 \uc77c\ubc18\uc801\uc778 rwx \ubaa8\ub4dc \ubd80\ud130 \ubd05\uc2dc\ub2e4.<\/P>
\n
chmod \uc22b\uc790(\ud37c\ubbf8\uc158) \ud30c\uc77c\uc774\ub984 <\/P>
\n
\ubcf4\ud1b5 \uc774\ub7f0 \ubc29\ubc95\uc744 \ub9ce\uc774 \uc0ac\uc6a9\ud569\ub2c8\ub2e4. \uc774\ub7f0 \ubc29\ubc95\uc678\uc5d0\ub3c4 \uc22b\uc790 \ub300\uc2e0 \uc9c1\uc811 \ud37c\ubbf8\uc158 \ubaa8\ub4dc \uc774\ub984\uc744 \ub123\uc744
\uc218\ub3c4 \uc788\uc9c0\ub9cc \uc22b\uc790\ub97c \uc870\ud569\ud574\uc11c \ub9cc\ub4dc\ub294 \uac83\uc774 \uac00\uc7a5 \ud3b8\ud569\ub2c8\ub2e4.<\/P>
\n
\uc22b\uc790\ub780\uc5d0\ub2e4 \ub123\uc744 \uc218 \uc788\ub294 \uaddc\uce59\uc740 \uc544\uc8fc \uac04\ub2e8\ud569\ub2c8\ub2e4.
r = 4 , w = 2 , w = 1 \ub85c \uacc4\uc0b0\uc744 \ud558\ub294 \uac70\uc8e0.
\ub610\ud55c \uc138\ub2e8\uc73c\ub85c \ub098\ub220\uc9c0\ub294 \ud37c\ubbf8\uc158\uc744 \uc0dd\uac01\ud574\uc57c \uaca0\uc8e0.
rwxrwxrwx \uc774\ub7f0 \uc2dd\uc73c\ub85c\uc694.. \uc790 \uadf8\ub7ec\uba74 \uc774\ub7f0 \uc608\uc81c\ub97c \ubcf4\uc2dc\uba74 \uae08\ubc29 \uaddc\uce59\uc744 \uc54c \uc218
\uc788\uc744\uaebc\uc5d0\uc694.<\/P>
\n
\ud37c\ubbf8\uc158 : rwxrwxrwx
4+2+1 + 4+2+1 + 4+2+1 = 777 ( chmod 777 file_name )<\/P>
\n
\ud37c\ubbf8\uc158 : rwx—r-x
4+2+1 + 0+0+0 + 4+0+1 = 705 ( chmod 705 file_name )<\/P>
\n
\ud37c\ubbf8\uc158 : r-xrw—x
4+0+1 + 4+2+0 + 0+0+1 = 561 ( chmod 561 file_name )<\/P>
\n
\ud37c\ubbf8\uc158 : –x–x–x
0+0+1 + 0+0+1 + 0+0+1 = 111 ( chmod 111 file_name )<\/P>
\n
\ub2e4\uc74c\uc740 setuid \uc124\uc815\uc774\uc5d0\uc694.
setuid \ub294 3\uc790\ub9ac \uc22b\uc790\uac00 \uc544\ub2cc \ud558\ub098\ub354 \ucd94\uac00\ud574\uc11c \uc0ac\uc6a9\ud574\uc694. 4\uc790\ub9ac \uc22b\uc790 \uc8fc\uc758 \ud574\uc57c \ud560 \uc810\uc740 setuid
\uac00 \uac78\ub9b0 \ud504\ub85c\uadf8\ub7a8\uc740 \uc2e4\ud589\uad8c\ud55c\uc774 \uc788\uc5b4\uc57c \ud574\uc694.<\/P>
\n
\ud37c\ubbf8\uc158 : rws——
4 + 4+2+1 + 0+0+0 + 0+0+0 = 4700 ( chmod 4700 file_name )<\/P>
\n
\ud37c\ubbf8\uc158 : –sr-xr-x
4 + 0+0+1 + 4+0+1 + 4+0+1 = 4155 ( chmod 4155 file_name )<\/P>
\n
* \ub9cc\uc57d 4155 \uac00 \uc544\ub2cc 4055 \ub85c \ud558\uba74 \uc2e4\ud589\uc774 \uc548\ub418\uc8e0.
# chmod 4055 sh
# ls -al sh
—Sr-xr-x 1 bugscan informix 88620 Aug 20 02:54 sh*
# .\/sh
.\/sh: Permission denied.
# chmod 4155 sh
# ls -al sh
—sr-xr-x 1 bugscan informix 88620 Aug 20 02:54 sh*
# .\/sh
$ whoami bugscan
<\/P><\/p>\n","protected":false},"excerpt":{"rendered":"
SetUID\uc640 Permission \uc7a0\uae50 \uc9ec\uc744 \ub0b4\uc11c SetUID \ub77c\ub294 \uac83\uc5d0 \ub300\ud574 \uc9da\uace0 \ub118\uc5b4\uac00\uace0\uc790 \ud569\ub2c8\ub2e4. SUID\uc5d0 \ub300\ud574\uc11c \uc54c\uae30 \uc704\ud574\uc11c\ub294 \ud37c\ubbf8\uc158(Permission)\uc5d0 \ub300\ud574\uc11c \uc54c\uc544\uc57c \ud558\uc8e0. 1. \ud37c\ubbf8\uc158\uc774 \uc65c \uc874\uc7ac\ud558\ub294\uac00? ; \uc720\ub2c9\uc2a4\ub294 \ub3c4\uc2a4\uc640\ub294 \ub2ec\ub9ac \uba40\ud2f0 \uc720\uc838 \uc6b4\uc601\uccb4\uc81c \uc785\ub2c8\ub2e4. \ub9ce\uc740 \uc0ac\ub78c\ub4e4\uc774 \ub3d9\uc2dc\uc5d0 \ud558\ub098\uc758 \uc11c\ubc84\uc5d0\uc11c \uc77c\uc744 \ud560 \uc218\uac00 \uc788\uc8e0. \uc70895\ub098 98, \ub3c4\uc2a4\uac19\uc740 \uc2dc\uc2a4\ud15c\uc5d0\uc11c\ub294 \ud55c\uac1c\uc758 \uc11c\ubc84\ub2f9 \ud55c\uba85\uc758 \uc0ac\ub78c\uc774 \uc0ac\uc6a9\ud560 \uc218 \uac00 \uc788\uc8e0. \uc774\ub807\uac8c \ucef4\ud4e8\ud130 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"spay_email":""},"categories":[405],"tags":[515,516],"jetpack_featured_media_url":"","amp_enabled":true,"_links":{"self":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/979"}],"collection":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=979"}],"version-history":[{"count":0,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/979\/revisions"}],"wp:attachment":[{"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=979"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=979"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=979"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}