Vulnerability Evaluation of Multimedia Subsystem Based on Complex Network

Transcription

1 JOURAL OF MULTIMDIA, VOL. 8, O. 4, AUGUST Vulnerabiliy valuaion of Mulimedia Subsysem Based on Complex ewor Xiaoling Tang Insiue of Higher ducaion Research, Jilin Business and Technology College, Changchun, China Absrac IP mulimedia subsysems bring huge securiy hreas o he IMS-based nex-generaion newors alhough hey bring IMS-based newor inegraion and business abiliy enhancemen. Therefore, he research on he vulnerabiliy of IP mulimedia subsysems aracs widespread aenion recenly. In his aricle, he securiy hreas of nex-generaion core newors are discussed firs. And hen we analyze he vulnerabiliy characerisics of IP mulimedia subsysems. In order o evaluae he vulnerabiliy of IP mulimedia subsysems effecively, his paper furher applies he complex newor heory o consruc he newor model of IP mulimedia subsysem and propose he vulnerabiliy assessmen indicaor by adoping enropy model. Finally, some simulaion experimens and resul analysis are provided o our evaluaion model. Boh heoreical analysis and numerical simulaions indicae ha he proposed vulnerabiliy measuremen is a simple and effecive new mehod o evaluae he overall vulnerabiliy of his ind of IP mulimedia subsysems. In addiion, he proposed mehod provides a new idea and scienific basis for he vulnerabiliy assessmen of IP mulimedia subsysems. Index Terms IP Mulimedia Subsysem, ewor Safey, Vulnerabiliy Assessmen, Complex ewor Theory, nropy Model I. ITRODUCTIO Many real-life newors such as he Inerne, power grids and oher self-organizing newors exhibi complex feaures [, 2, 3]. These newors are imporan componens of our daily lives. Their safeies can seriously impac he economic developmen and social sabiliy. Therefore, he relaed researches on he newor safey have araced increasing aenion in recen decades [4, 5, 6]. For compuer newors, heir securiy is more and more imporan. Therefore, i is urgen o develop a suie of measurable and quaniaive merics o evaluae heir vulnerabiliy and furher propose schemes o proec hem. specially, IP mulimedia subsysem is an imporan concep proposed by he mos auhoriaive indusry organizaions 3GPP in he field of 3G mobile communicaions in March 22 [7, 8]. As he core of he nex generaion newors, is funcion eniy is numerous, and he vulnerabiliy disribuion is complicaed [9,, ]. Only when he vulnerabiliy of IP mulimedia subsysems can be evaluaed effecively, we can find ou he ey facors which lead o he securiy performance hreas of IP mulimedia subsysems and conrol he source of securiy hreas wihin IP mulimedia subsysems effecively [2, 3]. Furhermore, we can obain he objecive evaluaion according o various vulnerabiliy impacs on IP mulimedia subsysems. And hen he resilience of IP mulimedia subsysems will be improved and enhanced. Recenly, 3GPP and 3GPP2 Organizaions have proposed he securiy sandards on IP mulimedia subsysems. However, he sudy on he safey of IP mulimedia subsysems is sill in is infancy, which is insufficien o mee he securiy needs. A he same ime, i is difficul o follow he newor safey sandard because he acual configuraion of IP mulimedia subsysems needs o consider he acual condiions and he specific newor needs. Furhermore, in he operaion and mainenance process of IP mulimedia subsysems, here exis oher facors, such as he human negligence and misaes and so on. All hese will lead o securiy hreas of IP mulimedia subsysems. In order o find ou he weanesses of IP mulimedia subsysems, he source of safey hreas and he possibiliy of leaed informaion, he vulnerabiliy assessmen of IP mulimedia subsysems are very imporan and demanding o solve. In his way, he proecion program of IP mulimedia subsysems can be obained. On his basis, we can furher selec and deermine he safey conrol measures o avoid ransfer or reduce he losses. The early IP mulimedia subsysems are he firs sep in he migraion pah. They olerae he differen nown limiaions of securiy which could be challenging o sele in real-life operaions. However, he early IP mulimedia subsysem is omi consciously bu no wihou emphasizing he imporance of considering he sharply decreased securiy [7]. Furhermore, he vulnerabiliy of IP mulimedia subsysem implemenaions and high level service provider securiy demands were examined. And hen an implemenaion mehod o provide he desired degree of safey for IP mulimedia subsysem deploymens was defined [4]. Considering ha communicaions service provider mus deermine how o handle he influences of securiy flaws, a new mehod was emphasized in reference [5], wih examples o deermine he influence of safey-relaed malfuncions and he ey design elemens which are relaed wih modeling service reliabiliy. However, he safey research resuls on IP mulimedia subsysem are relaively lacing in spie of he core posiion of IP 23 ACADMY PUBLISHR doi:.434/jmm

2 44 JOURAL OF MULTIMDIA, VOL. 8, O. 4, AUGUST 23 mulimedia subsysem in nex-generaion newors. So far, he vulnerabiliy evaluaion echnology of domesic and inernaional mainsream mainly consis of newor survivabiliy analysis echniques [6], aac ree echnology [7], graph-based newor vulnerabiliy analysis echniques [8, 9]. The above echnologies in solving he problem of vulnerabiliy have some defecs and shorcomings. Acually, he vulnerabiliy assessmen of IP mulimedia subsysem should be a complex nonlinear problem since he vulnerabiliy of IP mulimedia subsysems is uncerain. Considering ha IP mulimedia subsysems are in he core posiion in he nex generaion newors and he exising problems, in his aricle, he securiy hreas of nex-generaion core newors are discussed and he vulnerabiliy characerisics of IP mulimedia subsysems are analyzed firs. And hen we use complex newor heory o build a newor model of IP mulimedia subsysem. According o he characerisics of IP mulimedia subsysem newors, a new soluion for he vulnerabiliy evaluaion of IP mulimedia subsysem newors is pu forward on he basis of he enropy model. Finally, we provide some simulaion experimens and resul analysis o proof he effeciveness of our evaluaion model. Boh heoreical analysis and numerical simulaions indicae ha he proposed vulnerabiliy measuremen is a simple and effecive new mehod o evaluae he overall vulnerabiliy of his ind of IP mulimedia subsysems. In addiion, he proposed mehod presens a new soluion mehod for he vulnerabiliy measuremen of IP mulimedia subsysem newors and provides basis for he esablishmen of securiy policy of IP mulimedia subsysems. measures before he aac on he IP mulimedia subsysem newors are invesigaed. This mehod has a more pracical significance o service providers as well as he majoriy of users because i focuses on he difficuly and he impac ha an aacer explois he vulnerabiliy of IP mulimedia subsysem newors. An imporan consideraion is provided o maerial uilizaion cos and ime uilizaion cos which are no direcly associaed wih he vulnerabiliy of IP mulimedia subsysem newors, bu acually are closely relaed o he facors of heir vulnerabiliy uilizaion. On he basis of consideraion, we analyze he vulnerabiliy characerisics of IP mulimedia subsysems and furher presen he assessmen mehod. The proposed vulnerabiliy assessmen of IP mulimedia subsysems is considered saring wih he possibiliy of vulnerabiliy uilizaion firs. Secondly, he consequence of vulnerabiliy uilizaion is an imporan facor which is considered by aacers. Synheically considering above wo aspecs, we obain he following evaluaion facors of vulnerabiliy. The deailed represenaion is as follows. II. VULRABILITY OF IP MULTIMDIA SUBSYSTM AD IP MULTIMDIA SUBSYSTM TWORK Figure. Index sysem of vulnerabiliy assessmen model. A. Vulnerabiliy of IP Mulimedia Subsysem The vulnerabiliy research of compuer newors can be divided ino several problem areas which include vulnerabiliy definiion, vulnerabiliy idenificaion, and vulnerabiliy analysis and vulnerabiliy assessmen. In general, he main purpose of he vulnerabiliy assessmen is he righ vulnerabiliy scoring or raing, he qualiaive and quaniaive analysis of he sysem vulnerabiliy. The sysem can be a service, a compuer on he newor or he compuer newor. In he field of newor securiy, he vulnerabiliy assessmen and he inrusion deecion of sysems, firewalls, virus deecion are four elemens in newor securiy. The research for vulnerabiliy assessmen of IP mulimedia subsysems is sill in is infancy, here are no sysemaic research resuls up o now. Addiionally, i is difficul o obain he facors of vulnerabiliy assessmen. Therefore, according o he curren siuaion of vulnerabiliy assessmen of IP mulimedia subsysems, he analysis mehod of vulnerabiliy dimension srucure is inroduced in his paper firs. The proposed evaluaion mehod considers he securiy reasons of IP mulimedia subsysems mainly from malicious users or aacers perspecive. Defense IP mulimedia subsysems are vulnerable o aacs and malfuncions. The mos imporan reason is ha here are many weanesses in hemselves. Once an aacer explois hese vulnerabiliies, hey are easy o succeed. The vulnerabiliies of IP mulimedia subsysems include he sysem vulnerabiliy which exiss iniially and he poenial vulnerabiliy which is brough by he laer increased safey measures. In oher word, he vulnerabiliy of IP mulimedia subsysems refers o he number of loopholes in he sysem and he resuling damage degree o he poenial hreas. I is an imporan indicaor o measure safey performance of an IP mulimedia subsysem. In general, if he vulnerabiliy degree of an IP mulimedia subsysem is small, i is more secure. Here, he vulnerabiliy of IP mulimedia subsysems is divided ino four caegories: logic errors, sysem flaws, social engineering and sraegy negligence. ach caegory in he above four caegories can be subdivided ino several subcaegories. In order o be convenien o calculae hem, here he facor se of vulnerabiliy assessmen and is corresponding subse of facors are designed. According o he acual siuaion, he weigh is given according o various facors, as shown in Table. 23 ACADMY PUBLISHR

3 JOURAL OF MULTIMDIA, VOL. 8, O. 4, AUGUST TABL I. OUR PROPOSD VULRABILITY VALUATIO FACTORS OF IP MULTIMDIA SUBSYSTM Level indicaors Weighs Logic errors.25 Sysem flaws Social engineering Sraegy negligence Secondary indicaors Sysem bug; Hardware bug Firewall filering rules; Securiy conrol measures Adminisraor service qualiy; personnel securiy awareness of IP mulimedia subsysem Securiy policy defecs; Implemenaion effeciveness of securiy policy The corresponding level of he weigh of he higher level.65;.35.35;.65.4;.6.5;.5 Figure 2. Informaion exchange lin graph wihin IP mulimedia subsysem newor B. IP Mulimedia Subsysem ewor based on Complex ewor Theory Wih he rapid developmen of IP mulimedia subsysem, newor consisency rule becomes a very acive opic in newor dynamics. Since small world newors and scale-free newors are proposed, complex newors have become he popular research opic in various disciplines. Some basic conceps and characerisic quaniies such as he shores pah, degree disribuion, clusering coefficien, beweenness and so on are pu forward gradually o describe he opology characerisics and dynamic properies of complex newors. I is found ha here are wo basic characerisics which are large average clusering coefficien and shores pah. Similar wih social relaion feaure in social newor, he acual newors also include a communiy srucure. Tha is, he inner connecion beween nodes of each communiy is very close. These characerisics have paved he way for he sudy of IP mulimedia subsysems. Based on he characerisic analysis of he vulnerabiliy of IP mulimedia subsysems, he archiecure-based vulnerabiliy approach is adoped o invesigae IP mulimedia subsysem newors by combining complex newor heory. The archiecure of is given by is probabilisic conrol flow graph. In his aricle, a graph G is defined by a non-empy se of nodes H and a nonempy se of edges L : G ( H, L), where H v v2 v L { e, e2,, e M } {,,, } is he se of nodes and is he se of edges. The oal number of nodes in he se H is, and he oal number of edges in he se L is M. In an IP mulimedia subsysem, informaion exchange behavior always occurs a he poin. The main funcion of he subsysems is o connec wo relaively independen componens ogeher. We will also regard any pair of poins allow access as a lin, as is shown in Figure 2. Figure 3. Virual represenaion of IP mulimedia subsysem newor In he following, we mae ensure he componens of IP mulimedia subsysem newor. Then he exchange relaions of informaion and energy among componens are invesigaed he beween componens. When here is he exchange of maer or energy beween he wo componen nodes exising wihin he IP mulimedia subsysem, an edge beween hem is deermined. The odes represen he componens of he applicaion. The edges represen he flow of conrol among he componens. ewors can be direced or undireced. Undireced newors are composed by edges connec a pair of nodes in a ransiive fashion. everheless, direced newors are composed only by direced edges connecing a pair of nodes hrough a given direcion. In general, direced edges are showed by an arrow represening he direcion of he connecion beween a pair of nodes. Here, we will exrac IP mulimedia subsysem ino a direced newor. In order o obain he corresponding adjacency marices of IP mulimedia subsysem, we collec daa and invesigae he relaions among componen nodes and hen obain he adjacency marix. Figure 3 represens he probabilisic conrol flow graph of an IP mulimedia subsysem newor by using UCIT 6., which consiss of 6 nodes. III. PROPOSD SCHM For IP mulimedia subsysem newor, he wo main indicaor of he informaion flow is he imeliness and accuracy of he informaion ransmission, as well as 23 ACADMY PUBLISHR

4 442 JOURAL OF MULTIMDIA, VOL. 8, O. 4, AUGUST 23 informaion securiy, namely he newor vulnerabiliy. Considering hese hree aspecs, we use he enropy o consruc he vulnerabiliy assessmen model of IP mulimedia subsysem newor. Based on he above analysis of he vulnerabiliy of IP mulimedia subsysem newors, he uncerainy of microscopic sae of IP mulimedia subsysem newors is described by he enropy in he following. I is relaed wih he number of he possible microscopic saes under macroscopic saes and also wih he occurrence probabiliy of he differen microscopic saes. The enropy reflecs he realiy connecion beween he nodes wihin he newor. The maximum enropy m represens he maximum value of he newor enropy, which represens he mos chaoic sae of he IP mulimedia subsysem newor. The raio of he presen newor enropy and he maximum newor enropy reflecs he unorganized exen of he IP mulimedia subsysem newor. Therefore, we define he ordered degree of an IP mulimedia subsysem newor as follows. R () The value of R characerizes he degree of organizaion of he newor. I is larger, which means ha he ordered degree of newor is higher and heir organizaion is more efficien. In he following, we define he ordered degree of a newor based on he accuracy and newor survivabiliy during informaion ransmission of IP mulimedia subsysem newor respecively in his aricle. And hen we synheically consider he wo aspecs. In his way, newor evaluaion model is proposed on he basis of he consideraion for he accuracy of he response and he newor ani-desroying abiliy. ewor qualiy reflecs he accuracy of he informaion flow beween he nodes in he newor. The qualiy enropy characerizes he size of he uncerainies of informaion qualiy. The oal qualiy enropy is defined as follows. m ( ) (2) p ( )log p ( ) (3) where p ( ) is node o achieve he qualiy of he micro-sae probabiliy? The expression of p ( ) is as follows. p ( ) d d where d is he number of nodes which is direcly lined o node. I is also he above-menioned node degree in IP mulimedia subsysem newor. (4) The maximum qualiy enropy of IP mulimedia subsysem newor is defined as follows. m log d (5) Thus, he qualiy ordered degree is as following. R (6) m Cluser coefficien C represens he cluser level among nodes in he newor. I describes he aggregaion sae of nodes wihin newor. For he cluser coefficien of any node, he following definiion is adoped: C 2 d ( d ) where is he number of acual exising edges among d( d ) neighboring nodes of node. is he maximum 2 connecion number among all neighboring nodes of node. Thus, he average cluser coefficien of he enire IP mulimedia subsysem newor is as follows. C (7) C (8) Obviously, C. Ani-desroying abiliy reflecs he sabiliy size of he newor srucure under differen aac sraegy. Anidesroying enropy describes he uncerainy size of he newor srucure ani-desroying abiliy. Ani-desroying enropy of node characerizes he uncerainy size of he ani-desroying abiliy of node, which is defined as following. ( ) p ( )log p ( ),,2,..., (7) where p ( ) 2 is he microsaes ani-desroying probabiliy of node and he following expression of p ( ) 2 is adoped: p ( ) 2 C According o q. (7) and q. (8), we define ha he ani-desroying enropy of IP mulimedia subsysem newor is as following. ( ) 2 2 C p ( )log p ( ) 2 2 The maximum ani-desroying enropy of IP mulimedia subsysem newor is defined as follows. (8) (9) 23 ACADMY PUBLISHR

5 G R JOURAL OF MULTIMDIA, VOL. 8, O. 4, AUGUST m log C () Thus, he qualiy ordered degree is as following. R 2 2 () 2m The vulnerabiliy measuremen is denoed by R. In order o consider he wo main facors of he accuracy of he informaion ransmission and informaion securiy synheically, he following vulnerabiliy measuremen of IP mulimedia subsysem newor is adoped based on q. (6) and q. (). R R R (2) 2 where and are he weigh coefficiens respecively. In m is he same case, if R is larger, he ordered degree of IP mulimedia subsysem newor is higher. In oher words, IP mulimedia subsysem newor is more efficien. Therefore, he value of R could characerize he vulnerabiliy of IP mulimedia subsysem newor well. To mae a meaningful comparison, we inroduce anoher definiion o discuss he vulnerabiliy of he IP mulimedia subsysem newors. We invesigae heir global conneciviy. A parameer G is proposed o measure he global conneciviy, which is defined as follows. G (3) where is he number of he nodes which can mainain he normal operaions before cascading breadowns, and is he number of he nodes of he whole newor which can mainain he normal operaions a presen. We define ha he load of node is as following. L C ( ) B ( ) ij i jh ij ( ) (4) where ij is he number of all he shores pahs beween node i and node j, ( ) is he number of he shores ij pahs hrough node beween node i and node j. The capaciy of a node represens he maximum load ha he node can olerae. In IP mulimedia subsysem newors, he capaciy of a node is limied by he corresponding cos. Here, we assume ha he capaciy C of node o be proporional o is iniial load, i.e., C ( ) L () ij ( ) (5) i j H ij ( ) ( ) where he parameer is he olerance parameer which reflecs he resisance o he aacs and malfuncions, According o he acual siuaion, L () is calculaed by q.(4) and he capaciy C of node is calculaed by q.(5) in our simulaions. IV. UMRICAL RSULTS In he simulaions, we choose.5 and.5. We use Malab2 as a programming language. In order o implemen our model, he Floyd Warshall algorihm is uilized in his leer. This algorihm follows a dynamic programming mehod o calculae he shores pahs beween all verices of an IP mulimedia subsysem newor. Based on he proposed vulnerabiliy assessmen mehod of IP mulimedia subsysem newor, he IP mulimedia subsysem newor model including 6 nodes will be applied o illusrae he vulnerabiliy of he IP mulimedia subsysem newors which is subjeced o malicious aacs. The beweenness for a node is he number of shores pahs passing hrough he node. We adop he highes beweenness node-based aac o explore he vulnerabiliy phenomenon of he IP mulimedia subsysem newor. If here are some nodes have equivalen beweenness, we choose he node wih he highes degree as he aaced node Figure 4. The relaion beween he proposed measuremen R and he runime by removing he node wih highes beweenness under our model in he case of Figure 5. The relaion beween he damage size G and he runime by removing he node wih highes beweenness under our model in he case of.. 23 ACADMY PUBLISHR

6 R G G R 444 JOURAL OF MULTIMDIA, VOL. 8, O. 4, AUGUST Figure 6. The relaion beween he proposed measuremen R and he runime by removing he node wih highes beweenness under our model in he case of Figure 7. The relaion beween he damage size G and he runime by removing he node wih highes beweenness under our model in he case of Figure 8. The relaion beween he proposed measuremen R and he runime by removing he node wih highes beweenness under our model in he case of.3. In Figs. 4-9, he dynamical behaviors of our proposed vulnerabiliy measuremen based on enropy and he damage size during failure propagaion are repored for an IP mulimedia subsysem newor of 6 nodes a he cases of differen values of he parameer. To mae a meaningful comparison, From Figs. 4, 6 and 8, we can see ha he value of R for a larger cascade increases much more sharply han ha for a smaller one even a he very early sage of malfuncion propagaion when he node wih he larges beweenness is aaced. Therefore, he proposed vulnerabiliy measuremen of IP mulimedia subsysem newor can help us o idenify he larger damage a he very early sage of malfuncion propagaion. I is of grea significance in he prevenion of major accidens in IP mulimedia subsysems. I is because ha he major accidens are no disinc from he smaller malfuncions on he enire scales a he early period of acciden propagaion. In addiion, as shown in Figs. 4, 6 and 8, we also find ha he value of R increases o a pea value and hen decreases o a saionary value during he process of malfuncion propagaion. In oher words, i increases o a maximal value and hen mainains almos unchanged. This resul shows ha our mehod can mae us find he malfuncions and dissolve locally in ime. Thus, he malfuncions from propagaing hroughou he IP mulimedia subsysem newor are prevened effecively Figure 9. The relaion beween he damage size G and he runime by removing he node wih highes beweenness under our model in he case of.3. Figs. 5, 7 and 9 depic he dynamical evolving behaviors of damage size during he malfuncion propagaion in he IP mulimedia subsysem newor of 6 nodes, a he cases of differen values of he parameer. In many IP mulimedia subsysem newors, he parameer is severely limied by he sysem cos. Therefore, our simulaions adop differen values of parameer o invesigae he IP mulimedia subsysem newor. We examine he impac of differen node capaciy of α on he IP mulimedia subsysem newors, as is shown in Figs The comparison resuls of he dynamics of he value of R and damage scale R during malfuncion propagaion are shown in Figs. 4-. We can see ha he value of parameer has significan influence on he malfuncion propagaion in IP mulimedia subsysem newor. Since he value of parameer is limied by he cos of an IP mulimedia subsysem, we should consruc he load disribuion of he IP mulimedia subsysem newors as homogenous as possible o decrease he vulnerabiliy agains he major incidens. By simulaions, we see ha our resuls are in agreemen wih easily he real-life IP mulimedia 23 ACADMY PUBLISHR

7 JOURAL OF MULTIMDIA, VOL. 8, O. 4, AUGUST subsysem. For example, in an IP mulimedia subsysem, he more equal he exchange informaion capaciy is, he more sable he IP mulimedia subsysem becomes. Consequenly, our proposed vulnerabiliy evaluaion based on enropy can be used as an indicaor o measure and conrol he vulnerabiliy of IP mulimedia subsysem newors. V. COCLUSIO IP mulimedia subsysem newors provide a powerful IP session-based core for advanced services in nexgeneraion newors. They mus be suiable o mee cusomer needs and service provider. IP mulimedia subsysems are designed o be a generic service enabler plaform which includes he availabiliy requiremens of he presen elecommunicaion operaors newors. In order for faciliae he operaions of his complex and cosly archiecure, we will a pleny of aracive services obaining high user accepance. The vulnerabiliy of he IP mulimedia subsysem user equipmen is also a serious safey hrea. A presen, he vulnerabiliy sudy of IP mulimedia subsysems in is infancy, no more influence resuls are pu forward by auhoriaive expers or insiuions. Therefore, i is no easy for us o quanify each evaluaion aribues of he vulnerabiliy for IP mulimedia subsysem newors. There is oo lile safey and oo many resricions imposed upon he users and cusomers ha mae operaing adequae securiy of IP mulimedia subsysems such a grand challenge. The enropy is iniially inroduced as a hermodynamic concep. I is a measure for he sysem disorder. The enropy is widely used due o is unique conen and peneraion. Recenly, as a physical descripion of complex sysem srucure, he enropy is more and more aenion and becomes an imporan research ool for complex sysems in he heory of complex sysems [2, 2]. The macro significance of enropy is a measuremen for he uniformiy of he sysem energy disribuion. The change direcion of he complex sysem sae can be expressed by he enropy. The energy disribuion is more uniform, he greaer he enropy is. Based on his, in order o avoid subjecive weighing mehod of uncerainy caused by he vague and conroversial and deermine he scienific and reasonable vulnerabiliy evaluaion mehod, we inroduce he concep of enropy o explore he vulnerabiliy of IP mulimedia subsysem newors. In his paper, on he basis of he emergence complex newor heory in recen years, we analyze complex feaures of IP mulimedia subsysem newors and explore he facors of he vulnerabiliy uilizaion for IP mulimedia subsysem newors. Based on he vulnerabiliy analysis, we inroduce he complex newor o build a newor model according he feaures of IP mulimedia subsysems. The concep of he newor enropy is proposed o quanify he vulnerabiliy of IP mulimedia subsysem newors. Finally, we provide some simulaion experimens and resul analysis o confirm he effeciveness and he pracicaliy of our evaluaion model. 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