Share
Embed
Transcript
18 slides
-
'PSNBU4USJOH"UUBDLͱ Format String Attack(จࣈྻॻࣜܕ߈ܸ)ɺprintf() syslog() ͷ ॻࣜࢦఆͷͰ͖ΔؔΛѱ༻͠ɺ %s
%x ͱ͍ͬͨॻࣜτʔΫϯΛ ͍ɺελοΫͦͷଞͷϝϞϦҐஔͷ༰Λσʔλͱͯ͠ग़ྗ͞ ͤͨΓɺ%n τʔΫϯΛͬͯҙͷΞυϨεҐஔʹҙͷσʔλΛ ॻ͖ࠐ·ͤΔ͜ͱ͕Ͱ͖Δɻ ߈ܸ͕ޭ͢Ε࠷ѱͷ߹ɺίϯϐϡʔλͷ੍ޚΛୣΘΕΔɻ ͦ͏Ͱͳͯ͘ϓϩηε͕ҟৗऴྃ͢Δͷো͕ى͜ΓಘΔɻ -
੬ऑੑͷ͋ΔϓϩάϥϜ JODMVEFTUEJPI JODMVEFTUSJOHI JOUNBJO JOUBSHD DIBS BSHW<> \ DIBSCVG<>
QSJOUG < >CVGQaO CVG TUSODQZ CVG BSHW<> QSJOUG CVG QVUDIBS aO SFUVSO ^ ࢀরɿ ͍ΖςΫϊϩδʔ GPSNBUTUSJOHBUUBDLʹΑΔ(05PWFSXSJUFΛͬͯΈΔ QSJOUG T CVG -
ίϯύΠϧ࣌ͷҙ w 441 4UBDL4NBTI1SPUFDUJPO ༗ޮ ؔͷݺͼग़࣌͠ʹελοΫʹDBOBSZ ΧφϦΞ ͱݺΕΔ ͕ஔ͔Εɺ͜Ε͕ॻ͖͑ΒΕͨͱ͖ڧ੍ऴྃ͢ΔΑ͏ʹͳΔɻ w
"4-3 "EESFTT4QBDF-BZPVU3BOEPNJ[BUJPO ແޮ ॏཁͳσʔλྖҬͷҐஔʢ௨ৗɺϓϩηεͷΞυϨεۭؒʹ͓͚Δ࣮ߦϑΝ ΠϧͷجఈͱϥΠϒϥϦɺώʔϓɺ͓ΑͼελοΫͷҐஔؚ͕·ΕΔʣΛແ࡞ ҝʹஔ͢ΔίϯϐϡʔληΩϡϦςΟͷٕज़ w %&1 %BUB&YFDVUJPO1SFWFOUJPO ແޮ %&1Λ༗ޮʹ͢Δͱ࣮ߦෆՄೳͳϝϞϦྖҬ͔ΒίʔυΛ࣮ߦ͢Δ͜ͱͷ ࢭ͞ΕΔɻ -
ॻࣜࢦఆ w ൪ͷελοΫͷ༰Λ֬ೝ͍ͨ͠߹YͰ֬ೝͰ͖Δɻ Φϑηοτ BPVU""""YYYYYYYYYYY < >CVGYC⒎GF⒎ """"C⒎⒎FEGC⒎C⒎⒎FDC⒎⒎C⒎⒎FC⒎⒎
w OΛࢦఆ͢Δ͜ͱͰݱ࣌·ͰʹετϦʔϜ·ͨόοϑΝʔʹਖ਼ৗʹॻ͖ࠐ·Εͨจ ࣈΛϝϞϦόΠτͷΞυϨεʹॻ͖͑Δ͜ͱ͕Ͱ͖Δɻ w DͰࢦఆ͕ͨ͠ग़ྗ͞ΕΔɻ YBBCCDDEE͔ΒͷόΠτͷΞυϨεΛ ʹॻ͖͑Δ BPVUbaYEEaYDDaYCCaYBBDO` """"Y -
ҙͷΞυϨεΛॻ͖͑Δ YBBCCDDEEΛ̍όΠτͣͭYʹॻ͖͑Δ Φϑηοτ͕ͷ߹ laYEEaYDDaYCCaYBB aYEFaYDDaYCCaYBB aYEGaYDDaYCCaYBB aYFaYDDaYCCaYBBa YBBCCDDEEY Y
IIO YBBCCDDEFYY Y Y&' IIO YBBCCDDEGYY Y Y&' IIO YBBCCDDFYY Y Y&' IIO ˞όΠτͣͭॻ͖͑Δ߹IOɺόΠτͣͭॻ͖͍͑ͨ߹IIO -
(MPCBM0⒎TFU5BCMF ίϯύΠϧ࣌ʹڞ༗ϥΠϒϥϦΛμΠφϛοΫϦϯΫͨ͠߹ɺڞ༗ϥΠϒϥϦͷؔ(05 (MPCBM 0⒎TFU5BCMF ͱݺΕΔδϟϯϓςʔϒϧΛհͯ͠ݺͼग़͞ΕΔɻ YG QVTIYF YGF
DBMMYQSJOUG!QMU Y BEEFTQ Y Y NPWFBY %803%153<FCQYD> Y BEEFBY Y YD NPWFBY %803%153<FBY> YF TVCFTQ Y Y QVTIY Y QVTIFBY Y MFBFBY <FCQY> Y QVTIFBY Y DBMMYCTUSODQZ!QMU YE BEEFTQ Y Y TVCFTQ YD Y MFBFBY <FCQY> Y QVTIFBY Y DBMMYQSJOUG!QMU YD BEEFTQ Y YG TVCFTQ YD Y QVTIYB Y DBMMYBQVUDIBS!QMU Y BEEFTQ Y EJTBTY %VNQPGBTTFNCMFSDPEFGPSGVODUJPOQSJOUG!QMU Y KNQ%803%153ETYBD Y QVTIY YC KNQY &OEPGBTTFNCMFSEVNQ SFBEFMG4BPVU 4FDUJPO)FBEFST </S>/BNF5ZQF"EES0⒎4J[F&4'MH <>HPUQMU130(#*54B8" ,FZUP'MBHT 8 XSJUF " BMMPD 9 FYFDVUF . NFSHF 4 TUSJOHT * JOGP - MJOLPSEFS ( HSPVQ 5 5-4 & FYDMVEF Y VOLOPXO 0 FYUSB04QSPDFTTJOHSFRVJSFE P 04TQFDJpD Q QSPDFTTPS TQFDJpD -
JNQPSUʜ BEES@HPUJOU TZTBSHW<> BEES@CVGJOU TZTBSHW<> JOEFYJOU
TZTBSHW<> CVǦ CJOTIͰγΣϧىಈ͢Δ TIFMMDPEFaYaYEaYaYaYGaYGaYaYaYaYG aYaYaYFaYaYFaYaYaYaYFaYEaYaYCaYDEaY GPSJJOSBOHF CVG TUSVDUQBDL * BEES@HPU J CVG TIFMMDPEF BNBQ PSE TUSVDUQBDL * BEES@CVG B<> B<>B<> Y B<> B<>B<> Y B<> B<>B<> Y B<> B<>MFO CVG Y GPSJJOSBOHF CVG EDEIIO B<J> JOEFY J Q1PQFO <BPVU CVG> QXBJU ҙͷΞυϨεʹॻ͖͑Δ (05ͷΞυϨε CVGͷΞυϨε ࢀরɿ ͍ΖςΫϊϩδʔ GPSNBUTUSJOHBUUBDLʹΑΔ(05PWFSXSJUFΛͬͯΈΔ -
࣮ࢪ QVUDIBS͕ؔݺΕͨ࣌ʹTIFMMDPEFΛ࣮ߦ͍ͨ͠ͱࢥ͍·͢ɻ BPVU""""YYYYYYYYYYY < >CVGYC⒎GF⒎ """"C⒎⒎FEGC⒎C⒎⒎FDC⒎⒎C⒎⒎FC⒎⒎ PCKEVNQEKQMUBPVU %JTBTTFNCMZPGTFDUJPOQMU BQVUDIBS!QMU B
⒎B KNQ YB B QVTIY BC FC⒎⒎⒎ KNQ@JOJU YD γΣϧ͕ىಈ͢Δ (05ΞυϨε CVGΞυϨε JOEFY QZUIPOFYQQZYB9C⒎GFGC < >CVGYC⒎GFGC -
࣍ͷεςοϓ w %&1Λ༗ޮʹͨ͠߹Ͳ͏͢Δʁ ෮श %&1Λ༗ޮʹ͢Δͱ࣮ߦෆՄೳͳϝϞϦྖҬ͔ΒίʔυΛ࣮ߦ͢Δ ͜ͱͷࢭ͞Ε·͢ɻ ͱ͍͏͜ͱʂγΣϧίʔυ͕࣮ߦͰ͖ͳ͍ɻ w 3FUVSOUPMJCD ϓϩηε͕࣮ߦ͞ΕΔͱڞ༗ϥΠϒϥϦ͕ΞυϨεʹϩʔυ͞ΕΔɻ
ͦͷϩʔυ͞ΕͨΞυϨεͷϕʔεΞυϨε͔ΒΦϑηοτΛݩʹؔ Λݺͼग़ͤ·͢ɻ จࣈྻͳͲՄೳ -
࣍ͷεςοϓ w "4-3Λ༗ޮʹͨ͠߹Ͳ͏͢Δʁ ෮श ॏཁͳσʔλྖҬͷҐஔʢ௨ৗɺϓϩηεͷΞυϨεۭؒʹ͓͚Δ ࣮ߦϑΝΠϧͷجఈͱϥΠϒϥϦɺώʔϓɺ͓ΑͼελοΫͷҐஔؚ͕· ΕΔʣΛແ࡞ҝʹஔ͢ΔίϯϐϡʔληΩϡϦςΟͷٕज़ XJLJ͔Β w
ϒϧʔτϑΥʔε తͷΞυϨεʹͳΔ·ͰϒϧʔϑΥʔε͢Δ w /PQTMFE "4-3ͷϥϯμϜஔʹ͋Δఔൣғ͕ܾ·͍ͬͯΔͷͰɺγΣϧ ίʔυલʹ/01Λͨ͘͞ΜڬΉ͜ͱͰϒϧʔτϑΥʔεΛޭͤ͞Δ -
3FUVSOUPMJCD BEES@SFUBEESBEES@CVG P⒎TFU@SFUBEES CVGTUSVDUQBDL * BEES@SFUBEES CVG TUSVDUQBDL *
BEES@SFUBEES CVG TUSVDUQBDL * BEES@SFUBEES CVG TUSVDUQBDL * BEES@SFUBEES CVG TUSVDUQBDL * BEES@SFUBEES CVG TUSVDUQBDL * BEES@SFUBEES CVG TUSVDUQBDL * BEES@SFUBEES CVG TUSVDUQBDL * BEES@SFUBEES CNBQ PSE TUSVDUQBDL * MJCD@CBTF P⒎TFU@CJOTI BNBQ PSE TUSVDUQBDL * MJCD@CBTF P⒎TFU@TZTUFN C<> C<>C<> Y C<> C<>C<> Y C<> C<>C<> Y C<> C<>B<> Y B<> B<>B<> Y B<> B<>B<> Y B<> B<>B<> Y B<> B<>MFO CVG Y ࢀরɿ ͍ΖςΫϊϩδʔ 3&-30ͱGPSNBUTUSJOHBUUBDLʹΑΔϦλʔϯΞυϨεॻ͖͑ YC⒎⒎ Y TBWFEFCQ FCQ ɹYCFE NBJO͔ΒͷϦλʔϯΞυϨε Y BSHD YC⒎⒎G BSHW<> YC⒎⒎ Y TBWFEFCQ FCQ ɹYCFC 4ZTUFNؔ Y SFUVSOΞυϨε YC⒎⒎G ୈҰҾ -
·ͱΊ * 'PSNBU4USJOH"UUBDLͷΈ ɾQSJOUG TZTMPHͳͲͷؔͷॻࣜτʔΫϯΛͬͯҙͷΞυϨεҐஔ ʹҙͷσʔλΛॻ͖ࠐ·ͤΔ͜ͱ͕Ͱ͖Δɻ ** 'PSNBU4USJOH"UUBDLͰ&YQMPJU࡞ ɾCVGʹTIFMMDPEFΛૠೖ͢Δ
ɾ(05ʹ͋ΔؔͷΞυϨεΛݺͼग़͍ͨ͠ઌͷCVGͷΞυϨεʹ 'PSNBU4USJOH"UUBDLͷ੬ऑੑΛͬͯॻ͖͑Δɻ *** 'PSNBU4USJOH"UUBDLͰ&YQMPJUͷԠ༻ ɾ3FUVSOUPMJCDΛͬͨ&YQMPJUͷઆ໌