{"id":477282,"date":"2023-08-09T09:10:23","date_gmt":"2023-08-09T09:10:23","guid":{"rendered":""},"modified":"2023-11-29T15:03:54","modified_gmt":"2023-11-29T15:03:54","slug":"format-string-attack","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/format-string-attack\/","title":{"rendered":"T\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng"},"content":{"rendered":"<p>T\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng l\u00e0 m\u1ed9t lo\u1ea1i l\u1ed7 h\u1ed5ng b\u1ea3o m\u1eadt x\u1ea3y ra trong l\u1eadp tr\u00ecnh m\u00e1y t\u00ednh. N\u00f3 cho ph\u00e9p k\u1ebb t\u1ea5n c\u00f4ng khai th\u00e1c c\u00e1ch ch\u01b0\u01a1ng tr\u00ecnh x\u1eed l\u00fd c\u00e1c ch\u1ee9c n\u0103ng \u0111\u1ea7u v\u00e0o\/\u0111\u1ea7u ra \u0111\u01b0\u1ee3c \u0111\u1ecbnh d\u1ea1ng. K\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng l\u1ed7 h\u1ed5ng n\u00e0y \u0111\u1ec3 \u0111\u1ecdc d\u1eef li\u1ec7u nh\u1ea1y c\u1ea3m, s\u1eeda \u0111\u1ed5i n\u1ed9i dung b\u1ed9 nh\u1edb ho\u1eb7c th\u1eadm ch\u00ed th\u1ef1c thi m\u00e3 t\u00f9y \u00fd tr\u00ean h\u1ec7 th\u1ed1ng \u0111\u00edch. C\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng l\u00e0 m\u1ed1i quan t\u00e2m l\u1edbn \u0111\u1ed1i v\u1edbi c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m v\u00e0 qu\u1ea3n tr\u1ecb vi\u00ean h\u1ec7 th\u1ed1ng do ch\u00fang c\u00f3 kh\u1ea3 n\u0103ng l\u00e0m t\u1ed5n h\u1ea1i \u0111\u1ebfn t\u00ednh to\u00e0n v\u1eb9n v\u00e0 b\u1ea3o m\u1eadt c\u1ee7a h\u1ec7 th\u1ed1ng.<\/p>\n<h2>L\u1ecbch s\u1eed ngu\u1ed3n g\u1ed1c c\u1ee7a Format String Attack v\u00e0 l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u1ec1 c\u1eadp \u0111\u1ebfn n\u00f3<\/h2>\n<p>Kh\u00e1i ni\u1ec7m v\u1ec1 l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u01b0\u1ee3c \u0111\u01b0a ra \u00e1nh s\u00e1ng v\u00e0o cu\u1ed1i nh\u1eefng n\u0103m 1990. N\u00f3 \u0111\u01b0\u1ee3c ph\u1ed5 bi\u1ebfn r\u1ed9ng r\u00e3i nh\u1edd m\u1ed9t b\u00e0i b\u00e1o xu\u1ea5t b\u1ea3n n\u0103m 2000 c\u00f3 t\u1ef1a \u0111\u1ec1 \u201cKhai th\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng\u201d c\u1ee7a Kostya Kortchinsky. B\u00e0i vi\u1ebft \u0111\u00e3 th\u1ea3o lu\u1eadn chi ti\u1ebft v\u1ec1 vi\u1ec7c khai th\u00e1c l\u1ed7 h\u1ed5ng n\u00e0y v\u00e0 ch\u1ee9ng minh t\u00e1c \u0111\u1ed9ng ti\u1ec1m \u1ea9n c\u1ee7a n\u00f3 \u0111\u1ed1i v\u1edbi c\u00e1c h\u1ec7 th\u1ed1ng. K\u1ec3 t\u1eeb \u0111\u00f3, c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng \u0111\u00e3 \u0111\u01b0\u1ee3c nghi\u00ean c\u1ee9u r\u1ed9ng r\u00e3i, gi\u00fap hi\u1ec3u r\u00f5 h\u01a1n v\u00e0 c\u1ea3i thi\u1ec7n c\u00e1c bi\u1ec7n ph\u00e1p b\u1ea3o m\u1eadt trong ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m.<\/p>\n<h2>Th\u00f4ng tin chi ti\u1ebft v\u1ec1 Format String Attack<\/h2>\n<p>C\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng x\u1ea3y ra khi k\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 ki\u1ec3m so\u00e1t tham s\u1ed1 chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng trong h\u00e0m \u0111\u1ea7u v\u00e0o\/\u0111\u1ea7u ra \u0111\u01b0\u1ee3c \u0111\u1ecbnh d\u1ea1ng. Nh\u1eefng ch\u1ee9c n\u0103ng n\u00e0y, ch\u1eb3ng h\u1ea1n nh\u01b0 <code data-no-translation=\"\">printf()<\/code> V\u00e0 <code data-no-translation=\"\">sprintf()<\/code>, \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i \u0111\u1ec3 \u0111\u1ecbnh d\u1ea1ng v\u00e0 in d\u1eef li\u1ec7u. Trong c\u00e1c ng\u00f4n ng\u1eef nh\u01b0 C v\u00e0 C++, ch\u00fang cho ph\u00e9p nh\u00e0 ph\u00e1t tri\u1ec3n ch\u1ec9 \u0111\u1ecbnh c\u00e1c ph\u1ea7n gi\u1eef ch\u1ed7 (v\u00ed d\u1ee5: <code data-no-translation=\"\">%s<\/code> cho d\u00e2y, <code data-no-translation=\"\">%d<\/code> cho s\u1ed1 nguy\u00ean) v\u00e0 c\u00e1c gi\u00e1 tr\u1ecb t\u01b0\u01a1ng \u1ee9ng s\u1ebd \u0111\u01b0\u1ee3c hi\u1ec3n th\u1ecb. L\u1ed7 h\u1ed5ng ph\u00e1t sinh khi m\u1ed9t ch\u01b0\u01a1ng tr\u00ecnh truy\u1ec1n d\u1eef li\u1ec7u do ng\u01b0\u1eddi d\u00f9ng ki\u1ec3m so\u00e1t d\u01b0\u1edbi d\u1ea1ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng m\u00e0 kh\u00f4ng \u0111\u01b0\u1ee3c x\u00e1c th\u1ef1c h\u1ee3p l\u1ec7, d\u1eabn \u0111\u1ebfn h\u1eadu qu\u1ea3 kh\u00f4ng l\u01b0\u1eddng tr\u01b0\u1edbc \u0111\u01b0\u1ee3c.<\/p>\n<h2>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a Format String Attack v\u00e0 c\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng c\u1ee7a n\u00f3<\/h2>\n<p>\u0110\u1ec3 hi\u1ec3u c\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng c\u1ee7a m\u1ed9t cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng, \u0111i\u1ec1u c\u1ea7n thi\u1ebft l\u00e0 ph\u1ea3i n\u1eafm b\u1eaft \u0111\u01b0\u1ee3c ho\u1ea1t \u0111\u1ed9ng b\u00ean trong c\u1ee7a c\u00e1c h\u00e0m \u0111\u1ea7u v\u00e0o\/\u0111\u1ea7u ra \u0111\u01b0\u1ee3c \u0111\u1ecbnh d\u1ea1ng. Trong c\u00e1c ng\u00f4n ng\u1eef nh\u01b0 C, c\u00e1c h\u00e0m in \u0111\u01b0\u1ee3c \u0111\u1ecbnh d\u1ea1ng s\u1eed d\u1ee5ng ng\u0103n x\u1ebfp \u0111\u1ec3 truy c\u1eadp c\u00e1c \u0111\u1ed1i s\u1ed1 \u0111\u01b0\u1ee3c truy\u1ec1n cho ch\u00fang. Khi nh\u00e0 ph\u00e1t tri\u1ec3n cung c\u1ea5p m\u1ed9t chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng, h\u00e0m s\u1ebd l\u1eb7p qua chu\u1ed7i \u0111\u00f3 v\u00e0 t\u00ecm ki\u1ebfm c\u00e1c b\u1ed9 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng (v\u00ed d\u1ee5: <code data-no-translation=\"\">%s<\/code>, <code data-no-translation=\"\">%d<\/code>). \u0110\u1ed1i v\u1edbi m\u1ed7i m\u00e3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u00ecm th\u1ea5y, h\u00e0m s\u1ebd c\u00f3 m\u1ed9t \u0111\u1ed1i s\u1ed1 t\u01b0\u01a1ng \u1ee9ng tr\u00ean ng\u0103n x\u1ebfp.<\/p>\n<p>Trong m\u1ed9t ch\u01b0\u01a1ng tr\u00ecnh c\u00f3 l\u1ed7 h\u1ed5ng, n\u1ebfu k\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 ki\u1ec3m so\u00e1t chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng, ch\u00fang c\u00f3 th\u1ec3 thao t\u00fang b\u1ed9 nh\u1edb c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh b\u1eb1ng c\u00e1ch khai th\u00e1c nh\u1eefng c\u00e1ch sau:<\/p>\n<ol>\n<li><strong>B\u1ed9 nh\u1edb \u0111\u1ecdc<\/strong>: B\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c c\u00f4ng c\u1ee5 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng nh\u01b0 <code data-no-translation=\"\">%x<\/code> ho\u1eb7c <code data-no-translation=\"\">%s<\/code>, k\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 r\u00f2 r\u1ec9 n\u1ed9i dung c\u1ee7a ng\u0103n x\u1ebfp ho\u1eb7c c\u00e1c v\u00f9ng b\u1ed9 nh\u1edb kh\u00e1c c\u00f3 th\u1ec3 ch\u1ee9a th\u00f4ng tin nh\u1ea1y c\u1ea3m.<\/li>\n<li><strong>B\u1ed9 nh\u1edb vi\u1ebft<\/strong>: C\u00f4ng c\u1ee5 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng nh\u01b0 <code data-no-translation=\"\">%n<\/code> cho ph\u00e9p k\u1ebb t\u1ea5n c\u00f4ng ghi d\u1eef li\u1ec7u v\u00e0o \u0111\u1ecba ch\u1ec9 b\u1ed9 nh\u1edb \u0111\u01b0\u1ee3c ch\u1ec9 ra b\u1edfi \u0111\u1ed1i s\u1ed1 t\u01b0\u01a1ng \u1ee9ng. \u0110i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 b\u1ecb l\u1ea1m d\u1ee5ng \u0111\u1ec3 s\u1eeda \u0111\u1ed5i c\u00e1c bi\u1ebfn, con tr\u1ecf h\u00e0m ho\u1eb7c th\u1eadm ch\u00ed m\u00e3 c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh.<\/li>\n<li><strong>Thi h\u00e0nh m\u00e3 t\u00f9y \u00fd<\/strong>: N\u1ebfu k\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 ki\u1ec3m so\u00e1t chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng v\u00e0 cung c\u1ea5p c\u00e1c \u0111\u1ed1i s\u1ed1 ph\u00f9 h\u1ee3p, ch\u00fang c\u00f3 th\u1ec3 th\u1ef1c thi m\u00e3 t\u00f9y \u00fd b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng <code data-no-translation=\"\">%n<\/code> \u0111\u1ec3 ghi v\u00e0o m\u1ed9t con tr\u1ecf h\u00e0m v\u00e0 sau \u0111\u00f3 k\u00edch ho\u1ea1t vi\u1ec7c th\u1ef1c thi n\u00f3.<\/li>\n<\/ol>\n<h2>Ph\u00e2n t\u00edch c\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a Format String Attack<\/h2>\n<p>C\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng l\u00e0:<\/p>\n<ol>\n<li><strong>Ki\u1ec3m so\u00e1t chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng<\/strong>: K\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 ki\u1ec3m so\u00e1t chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng, chu\u1ed7i n\u00e0y x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng \u0111\u1ea7u ra v\u00e0 c\u00f3 th\u1ec3 thao t\u00fang truy c\u1eadp b\u1ed9 nh\u1edb.<\/li>\n<li><strong>Khai th\u00e1c d\u1ef1a tr\u00ean ng\u0103n x\u1ebfp<\/strong>: C\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng th\u01b0\u1eddng nh\u1eafm v\u00e0o ng\u0103n x\u1ebfp, v\u00ec c\u00e1c h\u00e0m \u0111\u1ea7u v\u00e0o\/\u0111\u1ea7u ra \u0111\u01b0\u1ee3c \u0111\u1ecbnh d\u1ea1ng s\u1eed d\u1ee5ng n\u00f3 \u0111\u1ec3 truy c\u1eadp c\u00e1c \u0111\u1ed1i s\u1ed1.<\/li>\n<li><strong>Thao t\u00e1c b\u1ed9 nh\u1edb<\/strong>: K\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 \u0111\u1ecdc ho\u1eb7c ghi v\u00e0o \u0111\u1ecba ch\u1ec9 b\u1ed9 nh\u1edb th\u00f4ng qua b\u1ed9 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng, c\u00f3 kh\u1ea3 n\u0103ng d\u1eabn \u0111\u1ebfn vi\u1ec7c ti\u1ebft l\u1ed9 th\u00f4ng tin ho\u1eb7c th\u1ef1c thi m\u00e3.<\/li>\n<\/ol>\n<h2>C\u00e1c ki\u1ec3u t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng<\/h2>\n<p>C\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n th\u00e0nh hai lo\u1ea1i ch\u00ednh:<\/p>\n<ol>\n<li><strong>T\u1ea5n c\u00f4ng \u0111\u1ecdc<\/strong>: C\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng n\u00e0y t\u1eadp trung v\u00e0o vi\u1ec7c khai th\u00e1c c\u00e1c c\u00f4ng c\u1ee5 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng \u0111\u1ec3 \u0111\u1ecdc th\u00f4ng tin nh\u1ea1y c\u1ea3m t\u1eeb b\u1ed9 nh\u1edb c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh, ch\u1eb3ng h\u1ea1n nh\u01b0 \u0111\u1ecba ch\u1ec9 ng\u0103n x\u1ebfp ho\u1eb7c d\u1eef li\u1ec7u m\u1eadt kh\u1ea9u.<\/li>\n<li><strong>Vi\u1ebft t\u1ea5n c\u00f4ng<\/strong>: Trong c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng n\u00e0y, m\u1ee5c ti\u00eau l\u00e0 thao t\u00fang b\u1ed9 nh\u1edb b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng b\u1ed9 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng \u0111\u1ec3 ghi d\u1eef li\u1ec7u v\u00e0o c\u00e1c \u0111\u1ecba ch\u1ec9 b\u1ed9 nh\u1edb c\u1ee5 th\u1ec3, cho ph\u00e9p k\u1ebb t\u1ea5n c\u00f4ng s\u1eeda \u0111\u1ed5i c\u00e1c bi\u1ebfn ho\u1eb7c con tr\u1ecf h\u00e0m.<\/li>\n<\/ol>\n<p>D\u01b0\u1edbi \u0111\u00e2y l\u00e0 b\u1ea3ng t\u00f3m t\u1eaft c\u00e1c ki\u1ec3u t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng:<\/p>\n<table>\n<thead>\n<tr>\n<th>Ki\u1ec3u t\u1ea5n c\u00f4ng<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>T\u1ea5n c\u00f4ng \u0111\u1ecdc<\/td>\n<td>Khai th\u00e1c c\u00e1c c\u00f4ng c\u1ee5 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng \u0111\u1ec3 \u0111\u1ecdc b\u1ed9 nh\u1edb<\/td>\n<\/tr>\n<tr>\n<td>Vi\u1ebft t\u1ea5n c\u00f4ng<\/td>\n<td>Khai th\u00e1c c\u00e1c c\u00f4ng c\u1ee5 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng \u0111\u1ec3 ghi b\u1ed9 nh\u1edb<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>C\u00e1c c\u00e1ch s\u1eed d\u1ee5ng T\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng, c\u00e1c v\u1ea5n \u0111\u1ec1 v\u00e0 gi\u1ea3i ph\u00e1p<\/h2>\n<h3>C\u00e1c c\u00e1ch s\u1eed d\u1ee5ng Format String Attack<\/h3>\n<p>K\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 khai th\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng trong nhi\u1ec1u t\u00ecnh hu\u1ed1ng kh\u00e1c nhau, bao g\u1ed3m:<\/p>\n<ol>\n<li><strong>\u1ee8ng d\u1ee5ng web<\/strong>: N\u1ebfu \u1ee9ng d\u1ee5ng web s\u1eed d\u1ee5ng d\u1eef li\u1ec7u do ng\u01b0\u1eddi d\u00f9ng cung c\u1ea5p d\u01b0\u1edbi d\u1ea1ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng m\u00e0 kh\u00f4ng c\u00f3 x\u00e1c th\u1ef1c th\u00edch h\u1ee3p, k\u1ebb t\u1ea5n c\u00f4ng c\u00f3 th\u1ec3 khai th\u00e1c \u0111i\u1ec1u n\u00e0y \u0111\u1ec3 x\u00e2m ph\u1ea1m \u1ee9ng d\u1ee5ng ho\u1eb7c m\u00e1y ch\u1ee7 c\u01a1 b\u1ea3n.<\/li>\n<li><strong>Giao di\u1ec7n d\u00f2ng l\u1ec7nh<\/strong>: C\u00e1c ch\u01b0\u01a1ng tr\u00ecnh s\u1eed d\u1ee5ng \u0111\u1ed1i s\u1ed1 d\u00f2ng l\u1ec7nh \u0111\u1ec3 x\u00e2y d\u1ef1ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng d\u1ec5 b\u1ecb t\u1ea5n c\u00f4ng n\u1ebfu ch\u00fang kh\u00f4ng x\u00e1c th\u1ef1c d\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o c\u1ee7a ng\u01b0\u1eddi d\u00f9ng.<\/li>\n<li><strong>C\u01a1 ch\u1ebf ghi nh\u1eadt k\u00fd<\/strong>: C\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng trong c\u01a1 ch\u1ebf ghi nh\u1eadt k\u00fd c\u00f3 th\u1ec3 cung c\u1ea5p cho k\u1ebb t\u1ea5n c\u00f4ng th\u00f4ng tin c\u00f3 gi\u00e1 tr\u1ecb v\u1ec1 h\u1ec7 th\u1ed1ng v\u00e0 t\u1ea1o \u0111i\u1ec1u ki\u1ec7n cho c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng ti\u1ebfp theo.<\/li>\n<\/ol>\n<h3>V\u1ea5n \u0111\u1ec1 v\u00e0 gi\u1ea3i ph\u00e1p<\/h3>\n<ol>\n<li><strong>X\u00e1c th\u1ef1c \u0111\u1ea7u v\u00e0o kh\u00f4ng \u0111\u1ea7y \u0111\u1ee7<\/strong>: Nguy\u00ean nh\u00e2n ch\u00ednh g\u00e2y ra l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng l\u00e0 do x\u00e1c th\u1ef1c \u0111\u1ea7u v\u00e0o kh\u00f4ng \u0111\u1ea7y \u0111\u1ee7. Nh\u00e0 ph\u00e1t tri\u1ec3n n\u00ean x\u00e1c th\u1ef1c d\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o do ng\u01b0\u1eddi d\u00f9ng ki\u1ec3m so\u00e1t tr\u01b0\u1edbc khi s\u1eed d\u1ee5ng d\u1eef li\u1ec7u \u0111\u00f3 l\u00e0m chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng.<\/li>\n<li><strong>H\u1ea1n ch\u1ebf s\u1eed d\u1ee5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng<\/strong>: B\u1ea5t c\u1ee9 khi n\u00e0o c\u00f3 th\u1ec3, nh\u00e0 ph\u00e1t tri\u1ec3n n\u00ean tr\u00e1nh s\u1eed d\u1ee5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng v\u1edbi d\u1eef li\u1ec7u do ng\u01b0\u1eddi d\u00f9ng ki\u1ec3m so\u00e1t. Thay v\u00e0o \u0111\u00f3, h\u00e3y c\u00e2n nh\u1eafc s\u1eed d\u1ee5ng c\u00e1c l\u1ef1a ch\u1ecdn thay th\u1ebf an to\u00e0n h\u01a1n nh\u01b0 n\u1ed1i chu\u1ed7i ho\u1eb7c th\u01b0 vi\u1ec7n \u0111\u1ecbnh d\u1ea1ng v\u1edbi ki\u1ec3m tra \u0111\u1ea7u v\u00e0o nghi\u00eam ng\u1eb7t.<\/li>\n<li><strong>T\u00ednh n\u0103ng b\u1ea3o m\u1eadt tr\u00ecnh bi\u00ean d\u1ecbch<\/strong>: C\u00e1c tr\u00ecnh bi\u00ean d\u1ecbch hi\u1ec7n \u0111\u1ea1i cung c\u1ea5p c\u00e1c c\u01a1 ch\u1ebf b\u1ea3o m\u1eadt, nh\u01b0 <code data-no-translation=\"\">-fstack-protector<\/code> t\u00f9y ch\u1ecdn trong GCC, \u0111\u1ec3 ph\u00e1t hi\u1ec7n v\u00e0 ng\u0103n ch\u1eb7n c\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng. S\u1eed d\u1ee5ng c\u00e1c t\u00ednh n\u0103ng nh\u01b0 v\u1eady c\u00f3 th\u1ec3 gi\u1ea3m thi\u1ec3u r\u1ee7i ro.<\/li>\n<\/ol>\n<h2>C\u00e1c \u0111\u1eb7c \u0111i\u1ec3m ch\u00ednh v\u00e0 so s\u00e1nh v\u1edbi c\u00e1c thu\u1eadt ng\u1eef t\u01b0\u01a1ng t\u1ef1<\/h2>\n<table>\n<thead>\n<tr>\n<th>Thu\u1eadt ng\u1eef<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>T\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng<\/td>\n<td>Khai th\u00e1c c\u00e1c c\u00f4ng c\u1ee5 x\u00e1c \u0111\u1ecbnh \u0111\u1ecbnh d\u1ea1ng \u0111\u1ec3 thao t\u00e1c b\u1ed9 nh\u1edb<\/td>\n<\/tr>\n<tr>\n<td>Tr\u00e0n b\u1ed9 nh\u1edb<\/td>\n<td>Ghi d\u1eef li\u1ec7u v\u01b0\u1ee3t qu\u00e1 gi\u1edbi h\u1ea1n c\u1ee7a b\u1ed9 \u0111\u1ec7m<\/td>\n<\/tr>\n<tr>\n<td>Ti\u00eam SQL<\/td>\n<td>Khai th\u00e1c c\u00e1c truy v\u1ea5n SQL v\u1edbi \u0111\u1ea7u v\u00e0o \u0111\u1ed9c h\u1ea1i<\/td>\n<\/tr>\n<tr>\n<td>T\u1eadp l\u1ec7nh ch\u00e9o trang<\/td>\n<td>\u0110\u01b0a c\u00e1c t\u1eadp l\u1ec7nh \u0111\u1ed9c h\u1ea1i v\u00e0o \u1ee9ng d\u1ee5ng web<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>M\u1eb7c d\u00f9 c\u00f3 m\u1ed9t s\u1ed1 \u0111i\u1ec3m t\u01b0\u01a1ng \u0111\u1ed3ng gi\u1eefa c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng v\u00e0 c\u00e1c l\u1ed7 h\u1ed5ng kh\u00e1c, nh\u01b0ng ph\u01b0\u01a1ng ph\u00e1p, m\u1ee5c ti\u00eau v\u00e0 h\u1eadu qu\u1ea3 khai th\u00e1c c\u1ee7a ch\u00fang kh\u00e1c nhau \u0111\u00e1ng k\u1ec3.<\/p>\n<h2>Quan \u0111i\u1ec3m v\u00e0 c\u00f4ng ngh\u1ec7 t\u01b0\u01a1ng lai li\u00ean quan \u0111\u1ebfn Format String Attack<\/h2>\n<p>Khi c\u00e1c ho\u1ea1t \u0111\u1ed9ng ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m \u0111\u01b0\u1ee3c c\u1ea3i thi\u1ec7n, c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n ng\u00e0y c\u00e0ng nh\u1eadn th\u1ee9c r\u00f5 h\u01a1n v\u1ec1 c\u00e1c l\u1ed7 h\u1ed5ng b\u1ea3o m\u1eadt nh\u01b0 t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng. V\u1edbi s\u1ef1 ra \u0111\u1eddi c\u1ee7a c\u00e1c ti\u00eau chu\u1ea9n m\u00e3 h\u00f3a an to\u00e0n, c\u00e1c c\u00f4ng c\u1ee5 ph\u00e2n t\u00edch m\u00e3 t\u1ef1 \u0111\u1ed9ng v\u00e0 ki\u1ec3m tra b\u1ea3o m\u1eadt th\u01b0\u1eddng xuy\u00ean, s\u1ed1 l\u01b0\u1ee3ng c\u00e1c l\u1ed7 h\u1ed5ng nh\u01b0 v\u1eady d\u1ef1 ki\u1ebfn s\u1ebd gi\u1ea3m theo th\u1eddi gian.<\/p>\n<p>Ngo\u00e0i ra, vi\u1ec7c ph\u00e1t tri\u1ec3n c\u00e1c ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh c\u00f3 t\u00ednh n\u0103ng an to\u00e0n b\u1ed9 nh\u1edb t\u00edch h\u1ee3p, nh\u01b0 Rust, c\u00f3 th\u1ec3 cung c\u1ea5p th\u00eam m\u1ed9t l\u1edbp b\u1ea3o v\u1ec7 ch\u1ed1ng l\u1ea1i c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng.<\/p>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng ho\u1eb7c li\u00ean k\u1ebft m\u00e1y ch\u1ee7 proxy v\u1edbi Format String Attack<\/h2>\n<p>C\u00e1c m\u00e1y ch\u1ee7 proxy, gi\u1ed1ng nh\u01b0 c\u00e1c m\u00e1y ch\u1ee7 do OneProxy cung c\u1ea5p, c\u00f3 th\u1ec3 \u0111\u00f3ng vai tr\u00f2 gi\u1ea3m thi\u1ec3u c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng. M\u00e1y ch\u1ee7 proxy \u0111\u00f3ng vai tr\u00f2 trung gian gi\u1eefa m\u00e1y kh\u00e1ch v\u00e0 m\u00e1y ch\u1ee7 m\u1ee5c ti\u00eau, cho ph\u00e9p ch\u00fang ki\u1ec3m tra v\u00e0 l\u1ecdc c\u00e1c y\u00eau c\u1ea7u \u0111\u1ebfn. B\u1eb1ng c\u00e1ch tri\u1ec3n khai c\u00e1c bi\u1ec7n ph\u00e1p b\u1ea3o m\u1eadt \u1edf c\u1ea5p \u0111\u1ed9 m\u00e1y ch\u1ee7 proxy, c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng ti\u1ec1m \u1ea9n c\u00f3 th\u1ec3 b\u1ecb ch\u1eb7n v\u00e0 ch\u1eb7n tr\u01b0\u1edbc khi ti\u1ebfp c\u1eadn m\u00e1y ch\u1ee7 m\u1ee5c ti\u00eau.<\/p>\n<p>M\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh \u0111\u1ec3:<\/p>\n<ol>\n<li><strong>L\u1ecdc \u0111\u1ea7u v\u00e0o c\u1ee7a ng\u01b0\u1eddi d\u00f9ng<\/strong>: M\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 x\u00e1c th\u1ef1c th\u00f4ng tin \u0111\u1ea7u v\u00e0o c\u1ee7a ng\u01b0\u1eddi d\u00f9ng tr\u01b0\u1edbc khi chuy\u1ec3n ti\u1ebfp n\u00f3 \u0111\u1ebfn m\u00e1y ch\u1ee7 m\u1ee5c ti\u00eau, ng\u0103n ch\u1eb7n c\u00e1c chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng \u0111\u1ed9c h\u1ea1i ti\u1ebfp c\u1eadn c\u00e1c \u1ee9ng d\u1ee5ng d\u1ec5 b\u1ecb t\u1ea5n c\u00f4ng.<\/li>\n<li><strong>T\u01b0\u1eddng l\u1eeda \u1ee9ng d\u1ee5ng web<\/strong>: M\u00e1y ch\u1ee7 proxy n\u00e2ng cao c\u00f3 th\u1ec3 k\u1ebft h\u1ee3p ch\u1ee9c n\u0103ng T\u01b0\u1eddng l\u1eeda \u1ee9ng d\u1ee5ng web (WAF), bao g\u1ed3m t\u00ednh n\u0103ng b\u1ea3o v\u1ec7 ch\u1ed1ng l\u1ea1i c\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng.<\/li>\n<li><strong>Ghi nh\u1eadt k\u00fd v\u00e0 gi\u00e1m s\u00e1t<\/strong>: M\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 ghi nh\u1eadt k\u00fd v\u00e0 gi\u00e1m s\u00e1t c\u00e1c y\u00eau c\u1ea7u \u0111\u1ebfn, gi\u00fap ph\u00e1t hi\u1ec7n v\u00e0 ph\u00e2n t\u00edch c\u00e1c n\u1ed7 l\u1ef1c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng ti\u1ec1m \u1ea9n.<\/li>\n<\/ol>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<p>\u0110\u1ec3 bi\u1ebft th\u00eam th\u00f4ng tin v\u1ec1 c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng, h\u00e3y xem x\u00e9t kh\u00e1m ph\u00e1 c\u00e1c t\u00e0i nguy\u00ean sau:<\/p>\n<ol>\n<li><a href=\"https:\/\/www.owasp.org\/images\/2\/26\/OWASPAppSecDC2006-MitjaK.pdf\" target=\"_new\" rel=\"noopener nofollow\">Khai th\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng<\/a> \u2013 B\u00e0i tr\u00ecnh b\u00e0y c\u1ee7a Mitja Kolsek v\u00e0 Kostya Kortchinsky t\u1ea1i OWASP AppSec DC 2006.<\/li>\n<li><a href=\"https:\/\/crypto.stanford.edu\/cs155\/papers\/formatstring-1.2.pdf\" target=\"_new\" rel=\"noopener nofollow\">L\u1ed7i chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng \u2013 C\u00e1i nh\u00ecn \u0111\u1ea7u ti\u00ean<\/a> \u2013 B\u00e0i vi\u1ebft c\u1ee7a Aleph One kh\u00e1m ph\u00e1 chuy\u00ean s\u00e2u v\u1ec1 c\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng.<\/li>\n<li><a href=\"https:\/\/owasp.org\/www-project-top-ten\/\" target=\"_new\" rel=\"noopener nofollow\">Top 10 c\u1ee7a OWASP<\/a> \u2013 Danh s\u00e1ch m\u01b0\u1eddi r\u1ee7i ro b\u1ea3o m\u1eadt \u1ee9ng d\u1ee5ng web h\u00e0ng \u0111\u1ea7u c\u1ee7a OWASP, bao g\u1ed3m c\u00e1c l\u1ed7 h\u1ed5ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng.<\/li>\n<\/ol>\n<p>T\u00f3m l\u1ea1i, c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng chu\u1ed7i \u0111\u1ecbnh d\u1ea1ng g\u00e2y ra r\u1ee7i ro \u0111\u00e1ng k\u1ec3 cho h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m, nh\u01b0ng b\u1eb1ng c\u00e1ch \u00e1p d\u1ee5ng c\u00e1c ph\u01b0\u01a1ng ph\u00e1p m\u00e3 h\u00f3a an to\u00e0n v\u00e0 t\u1eadn d\u1ee5ng kh\u1ea3 n\u0103ng c\u1ee7a m\u00e1y ch\u1ee7 proxy, nh\u00e0 ph\u00e1t tri\u1ec3n c\u00f3 th\u1ec3 ch\u1ed1ng l\u1ea1i c\u00e1c m\u1ed1i \u0111e d\u1ecda n\u00e0y v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n c\u0169ng nh\u01b0 b\u1ea3o m\u1eadt cho \u1ee9ng d\u1ee5ng v\u00e0 d\u1eef li\u1ec7u c\u1ee7a h\u1ecd.<\/p>","protected":false},"featured_media":497608,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-477282","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Format String Attack: Understanding the Vulnerability Exploited by Hackers<\/mark>","faq_items":[{"question":"What is a Format String Attack?","answer":"A Format String Attack is a type of security vulnerability that occurs in computer programming. It allows attackers to exploit the way a program handles formatted input\/output functions, potentially leading to unauthorized access, data leaks, or even code execution on the target system."},{"question":"How did Format String Attacks originate?","answer":"The concept of Format String Attacks was first highlighted in a 2000 paper titled \"Exploiting Format String Vulnerabilities\" by Kostya Kortchinsky. Since then, these attacks have been a significant concern in software development due to their potential to compromise system integrity and confidentiality."},{"question":"How does a Format String Attack work?","answer":"In a Format String Attack, the attacker manipulates the format string parameter in formatted input\/output functions, such as <code>printf()<\/code> and <code>sprintf()<\/code>. By controlling the format string, the attacker can read sensitive data, write to memory addresses, or even execute arbitrary code by exploiting certain format specifiers."},{"question":"What are the key features of a Format String Attack?","answer":"The key features of a Format String Attack include the attacker's ability to control the format string, exploit stack-based memory access, and manipulate memory contents through format specifiers."},{"question":"What types of Format String Attacks exist?","answer":"Format String Attacks can be classified into two main types:\r\n<ol>\r\n \t<li>Reading Attacks: Exploiting format specifiers to read sensitive data from the program's memory.<\/li>\r\n \t<li>Writing Attacks: Exploiting format specifiers to write data to specific memory addresses, enabling the modification of variables or function pointers.<\/li>\r\n<\/ol>"},{"question":"How can Format String Attacks be prevented?","answer":"To prevent Format String Attacks, developers should:\r\n<ul>\r\n \t<li>Validate user-controlled input before using it as a format string.<\/li>\r\n \t<li>Avoid using format strings with user-controlled data whenever possible.<\/li>\r\n \t<li>Utilize compiler security features like <code>-fstack-protector<\/code> to detect and prevent vulnerabilities.<\/li>\r\n<\/ul>"},{"question":"How can proxy servers like OneProxy help with Format String Attacks?","answer":"Proxy servers like OneProxy can aid in mitigating Format String Attacks by:\r\n<ul>\r\n \t<li>Filtering user input before forwarding it to the target server.<\/li>\r\n \t<li>Implementing Web Application Firewall (WAF) functionality to protect against format string vulnerabilities.<\/li>\r\n \t<li>Logging and monitoring incoming requests to detect and analyze potential attack attempts.<\/li>\r\n<\/ul>"},{"question":"Are there any other vulnerabilities similar to Format String Attacks?","answer":"While Format String Attacks are unique, there are other vulnerabilities in the realm of cybersecurity, such as Buffer Overflow, SQL Injection, and Cross-Site Scripting, each with distinct exploitation methods and consequences."},{"question":"How can I learn more about Format String Attacks?","answer":"For further information about Format String Attacks, you can explore the following resources:\r\n<ol>\r\n \t<li><a href=\"https:\/\/www.owasp.org\/images\/2\/26\/OWASPAppSecDC2006-MitjaK.pdf\" target=\"_new\">Exploiting Format String Vulnerabilities<\/a> - A presentation by Mitja Kolsek and Kostya Kortchinsky at OWASP AppSec DC 2006.<\/li>\r\n \t<li><a href=\"https:\/\/crypto.stanford.edu\/cs155\/papers\/formatstring-1.2.pdf\" target=\"_new\">The Format String Bug - A First Look<\/a> - A paper by Aleph One exploring format string vulnerabilities in-depth.<\/li>\r\n \t<li><a href=\"https:\/\/owasp.org\/www-project-top-ten\/\" target=\"_new\">OWASP Top Ten<\/a> - OWASP's top ten list of web application security risks, including format string vulnerabilities.<\/li>\r\n<\/ol>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/477282","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki"}],"about":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/types\/wiki"}],"version-history":[{"count":0,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/477282\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/497608"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=477282"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}