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Found 5 results

  1. Change your virtual location to the other side of the world. Useful when you want to get the best connection possible, add an extra layer of privacy, or use your favorite services when you’re away from home. Either let Freedome connect to your closest F-Secure Cloud, or select a virtual location from a set of countries. Handy if you’re traveling but want to follow a series on a streaming service (most block foreign IPs). Today’s world looks very different than it did 25 years ago when we started working with Internet security. Privacy issues and fundamental questions about our online freedom are now on everyone’s lips. F?Secure Freedome VPN (100% Discount)
  2. There's an extremely critical bug in the Xen, KVM, and native QEMU virtual machine platforms and appliances that makes it possible for attackers to break out of protected guest environments and take full control of the operating system hosting them, security researchers warned Wednesday. The vulnerability is serious because it pierces a key protection that many cloud service providers use to segregate one customer's data from another's. If attackers with access to one virtualized environment can escape to the underlying operating system, they could potentially access all other virtual environments. In the process, they would be undermining one of the fundamental guarantees of virtual machines. Compounding the severity, the vulnerability resides in a low-level disk controller, allowing it to be exploited when guest or host OSes alike run Linux, Windows, Mac OS X, or possibly other OSes. Researchers from security firm CrowdStrike, who first warned of the vulnerability, wrote: The vulnerability is the result of a buffer-overflow bug in QEMU's virtual Floppy Disk Controller, which is used in a variety of virtualization platforms and appliances. It is known to affect Xen, KVM, and the native QEMU client software, and it may affect others. VMware, Microsoft Hyper-V, and Bochs hypervisors are not affected. At publication time, patches were available from the Xen Project and the QEMU Project. RedHat has a patch here. There are also workarounds users can follow to lessen the risk of exploitation. The vulnerability is serious enough that users of other virtualization packages should immediately contact the developers to find out if they're susceptible. The bug has existed since 2004. There's no indication that the vulnerability is being actively exploited maliciously in the wild. Although the vulnerability is agnostic of the OS running both the guest and host, attack code exploiting the bug must have administrative or root privileges to the guest. The threat is greatest for people who rely on virtual private servers, which allow service providers to host multiple operating systems on a single physical server. Because virtual servers are often provided to different customers, it's common that they have administrative or root privileges to that guest OS that could be used to take over the underlying machine. CrowdStrike's advisory went on to state: For those who are unable to patch vulnerable software, CrowdStrike offered the following: The vulnerability has been dubbed Venom, short for virtualized environment neglected operations manipulation. Some people are already comparing its severity to Heartbleed, the catastrophic bug disclosed in April 2014 that exposed private cryptography keys, end-user passwords, and other sensitive data belonging to countless services that used the OpenSSL crypto library. At this early stage, it's too early to know if the comparison to Heartbleed is exaggerated, since at the moment there's no indication that Venom is being actively exploited. Tod Beardsley, a research manager at vulnerability assessment provider Rapid7, has indicated that the threat from Venom is likely not as serious. In an e-mailed statement, he wrote: Those limitations aside, there's an extremely broad range of platforms that are vulnerable to this exploit, and those platforms house servers used by banks, e-commerce providers, and countless other sensitive services. Given the large number of servers that are vulnerable and the extremely high value of the assets they contain, this security bug should be considered a top priority. Source
  3. Salutare,astazi o sa va prezint o comunitate numita "Connect Virtual Life". Aceasta comunitate are: -Server SAMP The Godfather --> Populat + Scripter bun. -Server de Counter-Strike Official -Server de WAR Official -Competitii sportive printre care si FIFA 2008 MANAGEMENT MODE * Aici puteti gasii sectiuni de CS/Photoshop de unde puteti descarca resurse si altele. FORUM Link: CVL PORTAL Link: CVL Server SA:MP : SAMP.CVL.RO:7777
  4. Dupa ce veti termina de citit acest tutorial veti cunoaste urmatoarele lucruti: Physical Memory Virtual memory Memory addressing (basics) Voi folosi cei mai simpli termeni ca fiecare sa inteleaga cum functioneaza Physical memory se refera la memoria fizica unde vin stocate datele Memoria fizica poate fi clasificata in 2 tipuri: Active memory Inactive Memory Physical Active memory (RAM) Aici vin stocate programele atunci cand vin executate.Termenul este folosit pentru a descrie cantitatea totala de memorie RAM instalata in calculator.(Se refera la memoria RAM).Poate fi paragonata cu un birou pe care se lucreaza cu diverse documente. Physical Inactive memory (hard drive) Aici vin stocate datele,termenul este folosit pentru a descrie accesarea datelor stocate in harddisk.Poate fi paragonat cu o biblioteca. Virtual memory Se refera la o arhitectura care este in grad sa simuleze un spatiu de memoriemai mare decat memoria Physical Active Memory (RAM).Presupunem ca vine definit un spatiu virtual cu adrese de la 1 la 10 .Acest spatiu poate fi folosit pentru a incarca programele atunci cand vin executate.Acum multi va veti intreba daca e o memorie virtuala unde stocheaza totusi datele.Ei bine aceasta memorie virtuala va stoca datele in RAM si in SWAP(care se afla pe har disk) Cum am mai spus memoria contine adrese unde pot fi stocate datele deoarece atunci cand se vor cere anumite date pentru a fi procesate de catre cpu trebuie sa stie de unde anume sa le scoata .Asadar pentru acest lucru vine impartita in diverse adrese.Adresele din memoria virtuala corespund la adresele de la memoria fizica(RAM) deoarece memoria virtuala este unul si acelasi lucru cu memoria fizica RAM doar ca numerele adreselor sunt diverse .Exemplu adresa 1 poate fi echivalenta la adresa 11 in RAM. In momentul in care un program va trebui sa stocheze o variabila in adresa 1 a memoriei virtuale aceasta adresa va fi tradusa in adresa 11 si variabila va fi stocata in RAM iar daca memoria RAM este plina va fi stocata in SWAP pana cand se va elibera spatiu in RAM.Sigurul lucru in legatura cu memoria virtuala pe care ar trebui sa il cunoasteti este ca este un spatiu virtual iar ceea ce vine stocat aici vine stocat in RAM sau in SWAP.Acest spatiu virtual se ocupa doar sa puna la dispozitie adrese de memorie cate programe care vor fi traduse si stocate in SWAP.Traducerea adreselor din memoria virtuala catre memoria fizica vine facuta prin MMU care este un component hardware.MMU traduce adresele virtuale in adrese fizice.MMU se ocupa de fiecare cerere de access la memorie de catre CPU. Memory addressing(basics) Note:voi defini cateva concepte basic deoarece in acest tutorial nu voi explica diversele tipuri de segmente (cei care au facut ASM sau C stiu la ce ma refer (ma voi referi la memory segmentation intrun alt tutorial unde voi explica conceptul de stack,heap,bss,text,data) Avem un executabil program1. Acest program cand vine executat va fi incarcat intro anumita memorie.Presupunem ca program1 are 5MB probabil va veti intreba cata memorie va ocupa acest program cand va fi executat.Program1 va ocupa 5MB de memorie + cata memorie a fost alocata in momentul in care a fost programat. Spre exemplu daca in program1 am stocat o variabila in memorie atunci cand va fi executat programul va ocupa 5mb + memoria variabilei declarate + alta memorie care a fost declarata chiar daca nu vine folosita. Unde va fi stocat acest program? In care memorie?Fiecare bucata din acest program va pleca la o anumita adresa a memoriei virtuale care va fi tradusa de catre MMU in adrese care corespund memoriei fizice RAM iar in cazul in care memoria fizica RAM este deja ocupata de catre alte programe acesta va fi stocat in swap asadar in momentul in care se va elibera memorie in RAM va trece in RAM. Cum arata o adresa de memorie? Vom crea cel mai simplu program posibil pentru a demonstra acest lucru #include <stdio.h> int main(void) { //Declar variabila var int var; //Stampez adresa in memorie a variabilei var printf ("Address of var is %p\n", &var); return 0; } o data executat acest program am obtinut urmatorul rezultat : Address of var is 0xbffff9ec Adresa variebilei acestui program este 0xbffff9ec care tradusa in decimal e 3221223916 In memorie adresa arata cam asa 10111111111111111111100111101100 Dupa cum vedeti eu am decis cum vreau sa fie stampata adresa variabilei var , daca careva prefera sa fie stampata intrun mod divers poate poate sa o faca Exemplu: #include <stdio.h> int main(void) { //Declar variabila var int var; //Stampez adresa in memorie a variabilei var in diverse moduri printf ("Address of var is %p\n", &var); //escaped hex C printf ("Address of var is %X\n", &var); //capital hex printf ("Address of var is %x\n", &var); //hex printf ("Address of var is %u\n", &var); //decimal return 0; } Output Address of var is 0xbffff9ec Address of var is BFFFF9EC Address of var is bffff9ec Address of var is 3221223916 Variabila var se gaseste in memoria virtuala la adresa 3221223916 intrun segment al memoriei chemat stack in acest caz (Memoria poate fi impartita in mai multe segmente dar cum am spus mai sus nu voi intra in detaliu)Nu toate variabilele se gasesc in stack . MMU va traduce adresa 3221223916 intro adresa fizica care este stocata in RAM.Daca memoria ram ar fi fost plina.MMU ar fi tradus adresa virtuala 3221223916 intro adresa fizica stocata in SWAP.Am creat o diagrama care explica unde si cum vine stocata memoria programelor care vin executate. Dupa cum vedeti in imagine memoria virtuala vine reprezentata doar de un tabel de adrese pe care MMU le va traduce in alte drese a memoriei fizice (RAM) sau (SWAP) in cazul in care RAM este ocupata. Daca aveti intrebari sunteti liberi sa le faceti ,in acest tutorial am folosit cat mai putini termeni informatici pentru a explica cum functioneaza memoria virtuala si memoria fizica, daca nu ati inteles ceva nu ezitati sa intrebati.
  5. In acest articol voi explica cum poate fi creat un conntainer in zolaris ,pentru a intelege mai bine intreaga structura vor trebui citite paginile manualului ,asadar pentru cei interesati sa puna in practica acest lucru RTFM.Diverse manuale le puteti gasi pe site-ul oficial oracle. In solaris un container este echivalent la un vps deoarece procedura este de virtualizare este facuta la nivelul sistemului si functioneaza pe acelasi principiu.Se pot crea diverse zone care pot fi host-uri separate.Zonele nu pot comunica intre ele decat folosind interfata de retea.Fiecare zona vine izolata si fiecare process ruleaza intrun container separat.Solaris poate virtualiza doar sistene solaris si exista 2 moduri pentru a crea aceste zone.Sper sa fie clar conceptul de zona sau container.O zona/container este un host, mai multe zone sunt mai multe host-uri virtuale.Inainte de a explica tipurile de zone care pot fi construite voi adauga urnmatoarele: Sistemul fizic vine definit ca o zona globala in solaris care este montatasub "/" si oricare alta zona vine creata in sistemul fizic va fi definita ca zona secondara "non global zone". Aceste zone pot fi create in 2 moduri 1.Sparse Root Zone Vine creata o zona al carui sistem de fisiere va fi partial mostenit din din sistemul de fisiere prezent in host-ul fizic.Spre exemplu anumite directoare a sistemului fizic vor fi de fapt in sharing cu noul host virtual.Acest lucru implica urmatoarele: Orice packet vine instalat in sistemul fizic va putea fi folosit si de catre sistemul virtual, bineinteles procesul fiecarui executabil va rula in sistemul virtual separat de catre sistemul fizic.Acest model ocupa aproximativ 100Mb pentru fiecare host virtual creat. Exemplu Sparse Root Zone: --------------------------- - **********- -########################*- -# * #*- -# FS * SHARE #*- -# * #*- -# ################*- -# # * *- -# HOST # * SRZ *- -# # * *- -# # * *- -######### **********- - HOST - --------------------------- HOST -> Host fizic SRZ -> Sparsed Root Zone (host virtual (vps)) FS -> Filesystem HOST (fizic) SHARE -> Filesystem HOST (fizic) in sharing cu host-ul virtual Note: Directoarele /usr /lib /sbin /platform /opt a sistemului fizic vor fi in sharing cu sistemul guest virtual. 2.Whole Root Zone Vine creata o zona care va contine o copie a fisierelor din host-ul fizic Fiecare pachet instalat in host-ul fizic nu va fi vazut de catre host-ul virtual, acesta fiind independent. Note: Directoarele /usr /lib /sbin /platform /opt a sistemului fizic vor fi copiate de catre sistemul virtual.Aceasta procedura va ocupa mai mult spatiu. Exemplu Whole Root Zone: --------------------------- - - -######### ********* - -# # * * - -# # * * - -# # * * - -# HOST # * WRZ * - -# FS1 # * FS2 * - -# # * * - -# # * * - -######### ********* - - HOST - --------------------------- HOST -> Host fizic FS1 ->Filesystem HOST (fizic) WRZ -> Host Virtual FS2 ->Filesystem WRZ (virtual) Ambele zone au aceleasi sintaxe pentru a fi create difera doar parametrul unui comand care va specifica tipul de zona. In urmatorul exemplu voi crea o zona "Sparse Root Zone": Zonele pot fi puse in orice tip de filesystem , chiar si pe discuri externe de storage.In exemple voi folosi ca path /export/home/zones Initial va trebui creat directorul care va fi containerul sistemului virtual il voi numi eclipse1 [eclipse]# pwd /export/home/zones [eclipse]# ls -ltr total 2 drwx------ 5 root root 512 Mar 6 04:22 eclipse1 [eclipse]# Pentru securitate am restrictionat acest director in asa fel incat doar user-ul root sa poata face modificari.Noul host virtual va avea o interfata logica care are ca baza interfata fizica a sistemului. zonecfg se ocupa de creare zonelor " zonecfg - set up zone configuration" Poate fi folosit interactiv sau chiar aplicand parametrii necesari in cmdline. [eclipse]# [COLOR="#00FF00"]zonecfg -z eclipse1[/COLOR] eclipse1: No such zone configured Use 'create' to begin configuring a new zone. zonecfg:eclipse1> [COLOR="#00FF00"]create [/COLOR] zonecfg:eclipse1> [COLOR="#00FF00"]set zonepath=/export/home/zones/eclipse1[/COLOR] zonecfg:eclipse1> zonecfg:eclipse1> [COLOR="#00FF00"]add net[/COLOR] zonecfg:eclipse1:net> zonecfg:eclipse1:net> [COLOR="#00FF00"]set address=192.168.123.107[/COLOR] zonecfg:eclipse1:net> [COLOR="#00FF00"]set physical=nfo0[/COLOR] zonecfg:eclipse1:net>[COLOR="#00FF00"]set defrouter=192.168.123.254[/COLOR] zonecfg:eclipse1:net>[COLOR="#00FF00"]info[/COLOR] net: address: 192.168.123.107 physical: nfo0 defrouter: 192.168.123.254 zonecfg:eclipse1:net> zonecfg:eclipse1:net> [COLOR="#00FF00"]end[/COLOR] zonecfg:eclipse1> zonecfg:eclipse1>[COLOR="#00FF00"]verify[/COLOR] zonecfg:eclipse1>[COLOR="#00FF00"]commit[/COLOR] zonecfg:eclipse1>[COLOR="#00FF00"]exit[/COLOR] [eclipse]# Aceasta procedura a creat un fisier de configurare XML unde a stocat toate informatiile pe care le-am introdus pentru noul sistem virtual. Fisierele pot fi gasite in /etc/zones [eclipse]# pwd /etc/zones [eclipse]# ls eclipse1.xml SUNWblank.xml SUNWlx.xml index SUNWdefault.xml SUNWtsoldef.xml [eclipse]# zoneadm - se ocupa de administratea zonelor "zoneadm - administer zones"Pentru a instala zona pe care am configurato se poate folosi urmatoarea sintaxa zoneadm -z eclipse install Preparing to install zone <eclipse1>. Creating list of files to copy from the global zone. Copying <1203> files to the zone. Initializing zone product registry. Determining zone package initialization order. Preparing to initialize <1203> packages on the zone. .................................................... Istalarea zonei va dura aproximativ 10 minute In urmatorul exemplu puteti vedea zonele instalate [eclipse]# zoneadm list -iv ID NAME STATUS PATH BRAND IP 0 global running / native shared - eclipse1 installed /export/home/zones/eclipse1 native shared [eclipse]# Note: Dupa cum observati fiecare zona are un id si un nume.Prima zona care vine identificata de catre valoarea 0 este de fapt sistemul fizic care am spus ca vine recunoscut ca o zona globala si se gaseste sub directorul "/" iar in acest moment e in running deoarece sistemul functioneaza [eclipse]# uptime 7:34am up 2 day(s), 58 min(s), 2 users, load average: 0.00, 0.00, 0.00 [eclipse]# Pentru a porni sistemul virtual pe care l-am creat vom folosi urmatorul comand [eclipse]# zoneadm -z eclipse1 boot [eclipse]# zoneadm list -iv ID NAME STATUS PATH BRAND IP 0 global running / native shared 12 eclipse1 running /export/home/zones/eclipse1 native shared [eclipse]# Urmatorul process confirma faptul ca zona e in running [eclipse]# ps -ef | grep z root 13496 13488 0 06:48:35 pts/1 0:00 sh -c more -s /tmp/mpzUaawA root 13531 1 0 07:35:59 ? 0:00 zoneadmd -z eclipse1 Un alt tool important pus la dispozitie de catre solaris este zlogin Poate fi folosit pentru a intra intro anumita zona avand un shell , e putin echivalent cu serviciul ssh are la baza acelasi principiu. Un parametru important a acestui comand este -C care stabileste o conexiune cu zone in consola.E important pentru a configura ambientul o data ce a fost instalat. zlogin -C eclipse1 Configurarile care au mai ramas de facut ar fi serverurile DNS, Language ,etc, toate acestea se pot face in mod interactiv o data ce a fost stabilita conexiunea in consola.Bineinteles pentru a face un simplu login in sistemul virtual se poate folosi urmatoarea sintaxa zlogin nume_zona [eclipse]# zlogin eclipse1 [Connected to zone 'eclipse1' pts/2] Last login: Tue Mar 6 06:47:30 on pts/2 Oracle Corporation SunOS 5.10 Generic Patch January 2005 # # Shutdown se poate face direct din sistemul virtual sau folosind unul din comenzile de administrare [eclipse]# zoneadm -z eclipse1 halt Note: Tin sa precizez faptul ca nu am setat optiunea set autoboot=true cand am configurat initial aceasta zona , asta inseamna ca nu va porni in momentul in care va face boot sistemul fizic, oricum fisierul de configurare poate fi modificat folosind comandul zonecfg.Pentru a cunoaste in amanunt fiecare parametru a acestor tool-uri de administrare rog sa recurgeti la man pages.Pentru a intra in mod manual in fiecare zona , identificati path-ul unde a fost creata si veti putea ajunge direct in sistemul de fisiere a aceste zone [eclipse]# cd /export/home/zones/eclipse1 [eclipse]# ls dev lu root [eclipse]# cd root [eclipse]# ls bin export lib opt sbin usr dev home mnt platform system var etc kernel net proc tmp [eclipse]# Evident plecand din sistemul fizic se pot doar explora si modifica fisierele dintro anumita zona, nu pot fi insa rulate procese cu drepturile userilor din zona (nu este echivalent cu un shell de login in sistemul guest care a fost virtualizat).Pentru a face login in sistemul care a fost virtualizat zlogin sau oricare alt serviciussh instalat in acel sistem va functiona.Daca sunt intrebari in legatura cu subiectul nu ezitati sa le faceti.
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