Modelling of Conflict Controlled Networks

Transcription

1 Oleksii Ignaenko 4, Glushkov Avenue, CSP 368, Kyiv 187, Ukraine ABSTRACT Game heoreical echniques have recenly become prevalen in many engineering applicaions, noably in communicaions. While developing an informaion nework managemen sysem ofen encounered a siuaion where one should deal wih malicious inrusion aemps aimed a obsrucing he rouing policy work. In his case, mehods of neworks managemen based on fluid models and a discree conrolled random walk model requires cerain changes. In his work we propose an approach based on conflic conrol poin of view ha could be useful for modeling of aacking acions and response behaviour of he sysem. 1. INTRODUCTION Today nework models are relaed o very differen areas informaion neworks, elecommunicaions, gas ransporaion and energy sysems, disribued producion processes. Complex neworks are everywhere. Unprecedened developing of informaion neworks (especially he Inerne gives example of dynamic inerconneced sysem. And his sysem is sill much less complex hen biological organisms or sociey of agens. For example, degree and mode of conneciviy in passive agens can combine o form images resembling crysals or snowflakes. The main focus wihin our own bodies is far more uiliarian. Endocrine, immune, and vascular sysems adjus chemical reacions o mainain equilibrium in he face of ongoing aacks from disease and die. In biology his is called homeosasis. In regulaion of a nework i is called conrol. So, here is need for mehods o model neworks in order o capure essenial srucure, dynamics, and uncerainy. Based on hese models one could explore ways o visualize nework behaviour so ha effecive conrol echniques can be synhesized and evaluaed. According o [1], modelling for he purposes of conrol and he developmen of conrol echniques for ruly complex neworks has become a major research aciviy over he pas wo decades. Informaion nework applicaions are especially imporan because hey inerfere wih almos all sides of human aciviy. As a resul, securiy and reliabiliy of informaion flows direcly affec he qualiy of service, efficiency and overall economic developmen of enire indusries. Reliable working of he informaion neworks has become vial for our day-o-day ransacions for he mos organizaions. Tha s why he Inerne becomes an aracive arge for cyber crime. Financially moivaed, he crime we see oday becomes more disribued, sophisicaed and dangerous. A few years ago aackers widely use remoely exploiing servers idenified by scanning he Inerne for vulnerable nework services. Significan facs of such scanning aacks were compuer worms such as Code Red and SQL Slammer. Their huge scale hreaens working of whole he Inerne a risk; for example, SQL Slammer generaed raffic sufficien o mel down backbones. Consequenly, academia and indusry developed effecive ways o forify he nework perimeer agains such aacks. Unforunaely, adversaries similarly changed acics moving away from noisy scanning o more sealhy aacks. No only did hey change heir acics, bu also heir moivaion. Previously, large-scale aacks were mosly expression of echnical superioriy. Now, cyber criminal are moivaed by economic benefis. They ry o no only exploi and seize conrol of compromised sysems for as long as possible bu o urn heir asses ino revenue. RTO-MP-MSG

2 Repor Documenaion Page Form Approved OMB No Public reporing burden for he collecion of informaion is esimaed o average 1 hour per response, including he ime for reviewing insrucions, searching exising daa sources, gahering and mainaining he daa needed, and compleing and reviewing he collecion of informaion. Send commens regarding his burden esimae or any oher aspec of his collecion of informaion, including suggesions for reducing his burden, o Washingon Headquarers Services, Direcorae for Informaion Operaions and Repors, 115 Jefferson Davis Highway, Suie 14, Arlingon VA -43. Respondens should be aware ha nowihsanding any oher provision of law, no person shall be subjec o a penaly for failing o comply wih a collecion of informaion if i does no display a currenly valid OMB conrol number. 1. REPORT DATE OCT 9. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Modelling of Conflic Conrolled Neworks 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 4, Glushkov Avenue, CSP 368, Kyiv 187, Ukraine 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 1. SPONSOR/MONITOR S ACRONYM(S) 1. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release, disribuion unlimied 11. SPONSOR/MONITOR S REPORT NUMBER(S) 13. SUPPLEMENTARY NOTES See also ADA RTO-MP-MSG-69 Curren Uses of M&S Covering Suppor o Operaions, Human Behaviour Represenaion, Irregular Warfare, Defence agains Terrorism and Coaliion Tacical Force Inegraion (Uilisaion acuelle M&S couvran le souien aux operaions, la represenaion du comporemen humain, la guerre asymerique, la defense conre le errorisme e l inegraion d une force acique de coaliion). Proceedings of he NATO RTO Modelling and Simulaion Group Symposium held in Brussels, Belgium on 15 and 16 Ocober 9., The original documen conains color images. 14. ABSTRACT Game heoreical echniques have recenly become prevalen in many engineering applicaions, noably in communicaions. While developing an informaion nework managemen sysem ofen encounered a siuaion where one should deal wih malicious inrusion aemps aimed a obsrucing he rouing policy work. In his case, mehods of neworks managemen based on fluid models and a discree conrolled random walk model requires cerain changes. In his work we propose an approach based on conflic conrol poin of view ha could be useful for modeling of aacking acions and response behaviour of he sysem. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified 18. NUMBER OF PAGES 1 19a. NAME OF RESPONSIBLE PERSON Sandard Form 98 (Rev. 8-98) Prescribed by ANSI Sd Z39-18

3 The Web offers hem a powerful infrasrucure o compromise compuer sysems. Aackers achieve his by employing he Web o serve malicious Web conen capable of compromising users compuers and running special code on hem. This has been enabled due o he increased complexiy of Web browsers and he resuling vulnerabiliies ha come wih complex sofware. For example, a modern Web browser provides a powerful compuing plaform wih access o differen scriping languages, (for example, Javascrip as well as exernal plugins ha may no follow he same securiy policies applied by he browser (for example, Flash, Java). While hese capabiliies enable sophisicaed Web applicaions, hey also allow aackers o collec informaion abou he arge sysem and deliver explois specifically ailored o a user s compuer. Web aacks render perimeer defences ha disallow incoming connecions useless agains exploiaion as hackers use he browser o iniiae ou-bound connecions o download aack payloads. This ype of raffic looks almos idenical o he users normal browsing raffic and is no usually blocked by nework firewalls. Tha s why compuer and nework securiy nowadays has become a major prioriy for boh nework design and implemenaion. Nework engineers use simulaion ools o help hem undersand and develop complex sysem. I is an effecive ool o save ime and money during developmen and implemenaion. To be able o simulae complex sysems, modeling is a necessary foundaion. Wihou an accurae model of he sysem or process here will be no successful simulaion. Simulaion depends on verified and validaed models. Modeling and Simulaion (M&S) ools are become sandard procedure oday before building compuer neworks o save ime and money. M&S ools become more and more widespread o differen areas in compuer sciences as well as oher fields for represening simulaion of realiy. Is i possible wih help from M&S o simulae compuer/nework securiy mechanism such as firewalls, Virual Privae Nework (VPN), key disribuion, and wha are he consequences of a simulae compuer nework aack? If i works, wha is possible o simulae wih M&S ools? The possible opposie case could be; is i possible a all o simulae compuer nework aacks and compuer/nework securiy on a compuer oday wih an M&S ool? An ideal scenario for M&S ool would be if i could be used o model and simulae differen compuer nework aack mehods which es compuer and nework securiy. A nework engineer could predefine his/her compuer nework in advance in a simulaion ool such as OPNET before building he compuer nework in realiy o see wha will happen o he nework and/or nework nodes if he nework is aacked wih differen kind of aack echniques. The nework engineer would hen have a virual model of he nework inside of he simulaion ool and press a buon o see wha happens when he aack srikes. The simulaed nework will have nework nodes such as worksaions (wih differen kinds of services and Operaing Sysems (OS) such as; Windows, UNIX, and Mac OS), swiches, rouers, firewalls, Inrusion Deecion Sysem (IDS), and servers and oher ypes of producs you will find in a ypical compuer nework. The differen simulaed compuer nework aacks would be used as a predicion ool o see wha happen when aacks occurs on he nework and how good he securiy is in he simulaed nework. Which nodes in he compuer nework will be aacked and affeced of he aack? Will he whole nework go down because a sraegically node goes down? The fundamenal quesion of issue is; is i possible o use M&S for modeling and simulaion of compuer/nework securiy and compuer nework aacks. Nework aacks are pure conflic siuaion, so we should urn our aenion o heory of conflic beween players. Game heoreical echniques have recenly become prevalen in many engineering applicaions, noably in communicaions. Wih he emergence of cooperaion as a new communicaion paradigm, and he need for self-organizing, decenralized, and auonomic neworks, i has become imperaive o seek suiable game heoreical ools ha allow o analyze and o sudy he behavior and ineracions of he nodes in fuure communicaion neworks RTO-MP-MSG-69

4 In general, game heory can be divided ino wo branches: non-cooperaive and cooperaive game heory. Non-cooperaive game heory sudies he sraegic choices resuling from he ineracions among compeing players, where each player chooses is sraegy independenly for improving is own performance (uiliy) or reducing is losses (coss). In his conex, nework denial of service aacks could be considered as a cones beween wo players (aacker and defense sysem) a game or a conflic conrolled sysem.. CYBER CRIME. DENIAL OF SERVICE ATTACKS The Inerne (originally known as ARPANET) was firs creaed in 1969 as a research nework sponsored by he Advanced Research Projecs Agency (ARPA) of he Deparmen of Defense (DoD) in he Unied Saes of America. The original aim was o provide an open nework for researchers o share heir research resources. Therefore, openness and growh of he nework were he design prioriies while securiy issues less of a concern. The occurrence of he Morris Worm in 1988 marked he firs major compuer securiy inciden on he Inerne. However, he world was no so dependen on he Inerne as i is now. The Inerne was sill limied o research and educaional communiies unil he lae 199s. Hence, no much aenion was paid o Inerne securiy. In he las decade, he phenomenal growh and success of he Inerne is changing is radiional role. The Inerne is no longer jus a ool for he researchers. I has become he main infrasrucure of he global informaion sociey. Governmens use he Inerne o provide informaion o he ciizens and he world a large, and hey will increasingly use he Inerne o provide governmen services. Companies share and exchange informaion wih heir divisions, suppliers, parners and cusomers efficienly and seamlessly. Research and educaional insiues depend more on he Inerne as a plaform for collaboraion and as a medium for disseminaing heir research discoveries rapidly. Unforunaely, wih he growh of he Inerne, he aacks o he Inerne have also increased incredibly fas. According o CERT [], a cener of Inerne securiy experise locaed in he U.S., he number of repored Inerne securiy incidens has jumped from 6 in 1988 o 8,94 in, and he esimaed number of Inerne securiy incidens in 3 is 153,14. The growh in he number of incidens repored beween 1998 o 3 is shown in Figure 1. Figure 1: Number of Inerne securiy incidens More imporanly, radiional operaions in essenial services, such as banking, ransporaion, power, medicine, and defense are being progressively replaced by cheaper, more efficien Inerne-based applicaions. Hisorically, an aack o a naion's criical services involves acions ha need o cross a physical boundary. These acions can be inerceped and prevened by a naion's securiy services. However, he global conneciviy of he Inerne renders physical boundaries meaningless. Inerne based aacks can be launched anywhere in he world, and unforunaely no Inerne based services are immune from hese aacks. Therefore, he reliabiliy and securiy of he Inerne no only benefis on-line businesses, bu is also an issue for naional securiy. RTO-MP-MSG

5 A DoS aack is a malicious aemp by a single person or a group of people o disrup an online service. DoS aacks can be launched agains boh services, e.g., a web server, and neworks, e.g., he nework connecion o a server. The impac of DoS aacks can vary from minor inconvenience o users of a websie, o serious financial losses for companies ha rely on heir on-line availabiliy o do business. On February 9,, Yahoo, ebay, Amazon.com, E*Trade, ZDne, Buy.com, he FBI, and several oher Web sies fell vicim o DoS aacks resuling in subsanial damage and inconvenience [3]. As emergency and essenial services become relian on he Inerne as par of heir communicaion infrasrucure, he consequences of DoS aacks could even become life-hreaening. Hence, i is crucial o deer, or oherwise minimize, he damage caused by DoS aacks. In general, a denial of service (DoS) aack is any aack which makes an on-line service (e.g., Web Service) unavailable. The aack could involve a single packe (e.g., he \land" aack ) exploiing sofware bugs in a server, or a raffic sream wih a remendous number of packes ha conges he arge's server or nework. We define a bandwidh aack as any aack ha consumes a arge's resources hrough a massive raffic volume. In his hesis, we focus on bandwidh aacks, and henceforh we mean bandwidh aack when we refer o denial of service aacks unless oherwise saed. The disribued denial of service (DDoS) aack is a bandwidh aack whose aack raffic comes from muliple sources. To launch a DDoS aack, an aacker usually compromises many insecure compuers conneced o he Inerne firs. Then a DDoS aack is launched from hese compromised compuers. The reflecor aack is an aack where innocen hird-paries (reflecors) are used o bounce aack raffic from he aacker o he arge. A reflecor can be any nework device ha responds o any incoming packe, for example, a web server. The aacker can make he aack raffic highly disribued by using many reflecors. The reflecor aack is a ype of DDoS aack. Currenly we have numerous DoS aack ypes. Each aack use some special exploi of Inerne proocols or sofware weaknesses. For example, his aacks could be launched direcly overwhelming by large packes (UDP, ICMP flood), using reflecors (Smurf, Fraggle), sending oo long packes (Ping of Deah), wrong packes (Land). Recenly one can see progress in his field new aack ypes cause damage o compuer sysems. Novel ype of aack, wih a low average rae, explois he ransiens of a sysem s dynamic behavior. The low-rae aacks inroduce significan inefficiencies ha remendously reduce sysem capaciy or service qualiy. In he lieraure, his kind of nework assaul is called shrew aack or Reducion of Qualiy (RoQ) aack. Various aacks has special characerisic. In work [4] we propose following parameer se. (Fig.): Aack ype. Securiy expers segregae DoS aacks ino wo caegories: disribued (aack from many sources) and non-disribued (aack from one compuer). Aack direcion. Aack direcions divided on nework resources and arge resources. Aack scheme. Generally speaking, aack scheme can be direc (direc sending of malicious raffic), reflecor (raffic reflecs from oher compuers) or hidden (malicious raffic hidden in legal). Aack mehod. Mehod defines vulnerabiliy ha used during aack. Targeed aack uses vulnerabiliy of sofware, services, and proocols. The primary goal of a consumpion aack is o consume all possible available resources (usually nework resources) o shu down a sysem. Exploiive aacks arge bugs in operaing sysems RTO-MP-MSG-69

6 Figure : Nework Sysem 3. CONFLICT CONTROLLED NETWORKS. MODELLING AND SIMULATIONS Nework models are used o describe power grids, cellular elecommunicaions sysems, large scale manufacuring processes, compuer sysems, and even sysems of elevaors in large office buildings. Alhough he applicaions are diverse, here are many common goals (such ha, sabiliy, performance, robusness and flexibiliy). Alhough complexiy of he physical sysem is boh inimidaing and unavoidable in ypical neworks, for he purposes of conrol design i is frequenly possible o consruc models of reduced complexiy ha lead o effecive conrol soluions for he physical sysem of ineres. These idealized models also serve o enhance inuiion regarding nework behavior. Neworks considered here consis of finie se of nodes, each conaining finie se of buffers. Packes arrive from ouside he nework o various buffers. One or more servers process packes a a given node, afer which a packe eiher leaves he nework or visis anoher node (Fig. 3). ( v( k Buffers q 1 ( q ( ) Server u ( ) 1 u ( ) Figure 3: Nework node RTO-MP-MSG

7 A general fluid model can be described by he differenial equaion q Aq ( Bu( Cv(, (1) n where q ( is he n-dimensional vecor of queue process, ( : R R denoes he packe arrival rae, u ( - he rouing policy, v ( - aack policy. Marix A represens an inner nework consrucion, marix B - rouing process and C describes aack process. The conrolled differenial equaion (1) can be viewed as a sae space model, as frequenly used in conrol applicaions, wih conrols u (, v ( and independen funcion (. We consider model (1) as a saring poin o invesigae conflic problem of ineracion beween a rouing policy and an aacker. If a successful design is obained, we could generalize his soluion on he case of Markov processes [1, 5]. The problem of finding of conrol u ( can be described as follows. We choose a conrol funcion u ( in purpose of minimizing vecor q ( under several special condiions (e.g. for minimal ime) and any possible funcions v (, (. Le us fix some funcion u (, hen soluion of (1) can be found using following formula: q( e A( ) q( ) e A( ) Bu( d ) e A( ) Cv( ) d e A( ) ( ) d (). If we assume, ha A, B I, C and (, () could be rewriing as: q( q( ) u(. (3) This is well-known single server queue fluid model. The single server queue is a useful model for a dynamic invesigaion of very differen sysems. Now we inroduce an exension of he fluid model [1] in he case of conflic process [6]. Le us consider dynamic sysem defined for an iniial condiion q( ( q1 (, q( ) R by he sysem of linear equaions: q ( k q ( u ( ), 1( 1 q v( u ( ),. (5) ( Phase sae is described by he phase vecor q( ( q1 (, q( ) R, where q 1 ( R is he queue lengh a max ime. The queue lengh is subjec o he linear phase consrain q ( q for all. Parameer q ( R is associaed wih he aacker player which rying o overwhelm our nework (or maximize q 1( in oher words) using conrol parameer v (, v (, v (. By choosing v ( a ime aacker ses aack power ( q ( ) ) which is subjec o he linear phase consrain q( for all. Parameer q ( influences on queue q 1( wih a coefficien k. The oher player defender has a conrol vecor u( ( u1(, u( ). He divides his conrol resources beween wo direcions: u 1( - for service of he arrived packes, u ( ) - for couneracion of he aacker aciviy. Conrol parameer u ( is 1 ) RTO-MP-MSG-69

8 subjec of following consrains u (, u (, u u ( ), for all. 1 1( Suppose ha defender has informaion abou (, v ( and q ( a ime. Funcion describe packes arrival service a ime. Suppose he following assumpions hold: ( ) : R R n ( ) max for all ; ( - coninuous funcion. ( ) d in This model is sabilizable if sraegy gives by following formula v for iniial posiion such ha q ( ) q max ( max ) max in. Time opimal u( ( u1(,), where, q( u (., q( To solve (1) we should find an admissible sraegy u (, q(, v( ) and momen of ime T such ha q ( for all T. We denoe his sraegy u(, q(, v( ) as he soluion of game (5). Noe ha his resul mus be achieved over all an admissible funcions v (. Le us wrie equaions (5) in sandard form. Denoe k A, hen ( u1( q ( Aq( (6). v( u( Conrol ses are respecively U { u R : u1 u } and V { vr : v1 max, v }. We solve his problem using he idea of he firs direc mehod of Ponryagin [7, 8]. k ( q()) Theorem. Consider he conflic conrolled sysem (6). If v and q1( ) in q can consruc he soluion u ( and momen of ime T, such ha q ( for T. (for proof see [9]) max 1, hen we Simulaions Le us illusrae obained resul on he example. Consider he model (5). This model was implemened in discree even nework simulaion framework OMNeT++. OMNeT++ is an objec-oriened modular discree even nework simulaion framework. I has a generic archiecure, so i can be (and has been) used in various problem domains: modeling of wired and wireless communicaion neworks proocol modeling RTO-MP-MSG

9 modeling of queuing neworks modeling of muliprocessors and oher disribued hardware sysems validaing of hardware archiecures evaluaing performance aspecs of complex sofware sysems and in general, i can be used for he modeling and simulaion of any sysem where he discree even approach is suiable, and which can be convenienly mapped ino eniies communicaing by exchanging messages. OMNeT++ iself is no a simulaor of anyhing concree, bu i raher provides infrasrucure and ools for wriing simulaions. One of he fundamenal ingrediens of his infrasrucure is a componen archiecure for simulaion models. Models are assembled from reusable componens ermed modules. Well-wrien modules are ruly reusable, and can be combined in various ways like LEGO blocks. Modules can be conneced wih each oher via gaes (oher sysems would call hem pors), and combined o form compound modules. Modules communicae hrough message passing, where messages may carry arbirary daa srucures. Modules can may messages along predefined pahs via gaes and connecions, or direcly o heir desinaion; he laer is useful for wireless simulaions, for example. Modules may have parameers, which can be used o cusomize module behaviour, and/or o parameerize he model s opology. Graphical, animaing user inerfaces are highly useful for demonsraion and debugging purposes (Figure 4.). Figure 4: Nework Sysem OMNe++ has he queue simulaion library. This library includes modules for communicaion neworks modeling. The model (5) was developed using sandard and new modules (Figure 5.). I consiss of users, aacking source, several queues wih shared resource, classifier, rouer and sink nodes. Users send packes o a rouer. Rouer performs disribuion among queues for processing. Queues use par of resource for working (if resource no available queue wai some ime). Then packes go o DaaProcessing node and lef sysem RTO-MP-MSG-69

10 Aack source node ry o disrup working. Aacker sars he flooding aack by sending idenical packes o rouer. Defense sysem makes filraion and drop ou fixed percen of all flooding packes. Figure 5: Model of nework Graph of packes delay rae shown on Figure 6. Figure 6: Sysem dynamic 4. SUMMARY To make rapid advances in cyber securiy defense, we mus improve he sae of he ar in evaluaion of nework securiy mechanisms. Evaluaion is currenly impeded by lack of scienific rigor, lack of relevan and represenaive nework daa, inadequae models of defense mechanisms, and inadequae models of he nework and boh he background and aack raffic daa [1]. Numerous feaures mus sill be implemened, verified, and validaed before a serious aemp can be made for simulaing compuer and nework securiy in M&S fashion. Verified and validaed models of nework raffic and aack raffic mus be conduced o be able o make accurae simulaion of a real even. Differen aack models mus be fabricaed for verificaion and validaion before hey can be used for aack simulaion. Very imporan issue is a heoreical background of aack models. The mos naural approach for dealing wih hese inerconneced neworks sysems is heory of conflic conrolled processes or game heory. Game heory provides a formal analyical framework wih a se of mahemaical ools o sudy he complex ineracions among raional players. Throughou he pas decades, game heory has made revoluionary impac on a large number of disciplines ranging from engineering, economics, poliical science, philosophy, or even psychology. In recen years, here has been a significan growh in research aciviies ha use game heory for analyzing communicaion neworks. RTO-MP-MSG

11 This is mainly due o: he need for developing auonomous, disribued, and flexible mobile neworks where he nework devices can make independen and raional sraegic decisions; he need for low complexiy disribued algorihms ha can efficienly represen compeiive or collaboraive scenarios beween nework eniies. In his work we proposed model of nework sysem wih conflic based on he differenial game heory background. This approach could be useful for modeling of aacking acions and response behaviour of he sysem. The model was developed and simulaed using environmen OMNe++. Simulaions resuls presened on graphs. [1] S. Meyn, Conrol Techniques for Complex Neworks, Cambridge Universiy Press, 7. [] CERT/CC Saisics, URL hp:// [3] L. Garber. Denial-of-service aacks rip he Inerne". IEEE Compuer 33(4), 1-17 (). [4] O. Ignaenko, P. Andon. Couneracion o denial of service aacks in Inerne: approach concep // Problems of programming, -3, 8, P [5] D. Bersekas, Nework opimizaion: coninuous and discree models, Ahena Scienific, Belmond, [6] A.A. Chikrii, Conflic-conrolled Processes, Kluwer Academic Publisher, Boson-London- Dordrech, [7] M.S. Nikolskii, L.S. Ponryagin's Firs Direc Mehod in Differenial Games, Izda. Gos. Univ., Moscow, [8] L.S. Ponryagin, Seleced Scienific Papers, Vol., Nauka, Moscow, [9] O. Ignaenko Conflic modeling of single server queue wih inegral consrains // PMCCS: The Inernaional Workshop on Performabiliy Modeling of Compuer and Communicaion Sysems, Eger, Hungary, Sepember, 9. (acceped) [1] Deer/Deerlab based on emulab. A Laboraory for Securiy Research. Revived Mars 18, 5 a URL: hp:// RTO-MP-MSG-69