The Hacker's Encyclopedia 1998

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┌──────────────────┐ ╔═══════════════════════════════╗ ┌──────────────────┐ │ Founded By: │ ║ Network Information Access ║ │ Mother Earth BBS │ │ Guardian Of Time │─║ 12APR90 ║─│ NUP:> DECnet │ │ Judge Dredd │ ║ Guardian Of Time ║ │Text File Archives│ └────────┬─────────┘ ║ File 18 ║ └─────────┬────────┘ │ ╚═══════════════════════════════╝ │ │ ╔═══════════════════════════════╗ │ └────────────║ VMS: System Manager's Manual ║──────────┘ ║ Chapter 4.11 ║ ╚═══════════════════════════════╝ Here is Chapter 4 of 11 Chapters, concerning the VMS: System Manager's Manual. Once you have download all 11 chapters, you will be able to enter a Vax system and hack your own accounts with the greatest of ease. MANAGING USERS As a system manager, it is your job to create and maintain user accounts on the system. To create accounts for users and effectively manage the use of the system, you must determine which users need access to the system and what system resources they require. Once you understand user needs, you can establish controls that customize the system appropriately. The VMS operating system provides the Authorize Utility (AUTHORIZE) to authorize and control the use of system resources by individual users. This chapter describes the use of AUTHORIZE to do the following: : Add a user account : Modify a user account : Remove a user account : List the user accounts See the Authorize Utility chapter in the Reference section for some information on AUTHORIZE. 4.1 THE USER AUTHORIZATION FILE (UAF) You manage VMS users by creating and maintaining user accounts, which control who can log in to the system and how it can be used. Use the Authorize Utility (AUTHORIZE) to do the following: : Create new records and modify existing records in the system user authorization file (SYS$SYSTEM:SYSUAF.DAT) and the network user authorization file (SYS$SYSTEM:NETPROXY.DAT) : Create new records and modify existing records in the rights database file (SYS$SYSTEM:RIGHTSLIST.DAT) Whenever a user logs in, the system uses the information contained in the user authorization file (UAF) to validate the login attempt, establish the account's environment, and create a process with appropriate attributes. In this way, the system restricts users to the resources you assign to each account. As system manager, you may want to create a private copy of SYSUAF. DAT in a directory other than SYS$SYSTEM as an emergency backup for the system SYSUAF.DAT file. Note that, to have an effect on user processes, any private version of SYSUAF.DAT must be copied to the SYS$SYSTEM directory and have the system user identification code (UIC). Because certain images (such as MAIL and SET) require access to the system UAF and are normally installed with the SYSPRV privilege, make certain that you always grant system access to SYSUAF.DAT. The authorization files are created with the following default protection: SYSUAF.DAT S:RWED, 0:RWED, G, W NETPROXY.DAT S:RWED, 0:RWED, G:RWED, W RIGHTSLIST.DAT S:RWED, 0:RWED, G:RWE, W:R If you need to maximize the protection for SYSUAF.DAT or NETPROXY.DAT, use the following DCL command (note, however, that RIGHTSLIST.DAT MUST BE WORLD-READABLE); $ SET PROTECTION=(S:RWED, O,G,W)SYSTEM$SYSTEM: FILENAME Using the Authorize Utility, you create and maintain UAF records by assigning values to various fields within each record. The values you assign identify the user, define the user's work environment, and control use of system resources. EXAMPLE 4-1 presents a typical UAF record for a nonprivileged user account. To gain access to a specific user record, set the default directory to SYS$SYSTEM, enter the command RUN AUTHORIZE to invoke the Authorize Utility, and enter the command SHOW username at the UAF> prompt. You can then enter AUTHORIZE commands and such as ADD and MODIFY to create new user accounts or change the information in the fields of an existing UAF account. EXAMPLE 4-1: SAMPLE UAF RECORD DISPLAY $ SET DEFAULT SYS$SYSTEM $ RUN AUTHORIZE UAF> SHOW WELCH USERNAME: WELCH OWNER: ROB WELCH ACCOUNT: INVOICE UIC: [21.51 ([INV.WELCH]) CLI: DCL TABLES: DCTABLES DEFAULT: USER3: [WELCH] LGICMD: LOGIN FLAGS: PRIMARY DAYS: MON TUE WED THU FRI SECONDARY DAYS: SAT SUN NO ACCESS RESTRICTIONS EXPIRATION: (NONE) PWDIMINIMUM: 6 LOGIN FAILS: 0 PWDLIFETIME: (NONE) PWCHANGE: 15APR88 13:58 LAST LOGIN: (NONE) (INTERACTIVE), (NONE) (NON-INTERACTIVE) MAXJOBS: 0 FILLM: 20 BYTLM: 8192 MAXACCTJOBS: 0 SHRFILLM: 0 PBYTOLM: 0 MAXDETACH: 0 BIOLM: 10 JTQUOTA: 1024 PRCLM: 2 DIOLM: 10 WSDEF: 150 PRIO: 4 ASTLM: 10 WSQUO: 256 QUEPRIO: 4 TQELM: 10 QSEXTENT: 512 CPU: (NONE) enqlm: 10 pgflquo: 10240 Authorized Privileges: TMPMBX NETMBX Default Privileges: TMPMBX NETMBX 4.1.1 SYSTEM-SUPPLIED UAF RECORDS The Authorize Utility proves a set of commands and qualifiers to assign values to any field in a UAF record. The software distribution with a new VMS system contains a UAF of four records: : DEFAULT - Serves as a template for creating user records in the UAF. A new user record is assigned the values of the DEFAULT record except where you explicitly override those values. Thus, whenever you add a new account, you need only specify values for fields that you want to be different. For example, the following AUTHORIZE command creates a new record having the same values as the DEFAULT RECORD, except that the password, UIC, and default directory fields are changed. UAF> ADD MARCONI/PASSWORD=QLP6YT9A/UIC=[033, 004]- _UAF> /DIRECTORY=[MARCONI] Section 4.2 gives an example of how to use AUTHORIZE to add a user account. NOTE: the default record cannot be renamed or deleted from the UAF. : FIELD - Permits DIGITAL Field Service personnel to check out a new system. The FIELD record should be disabled once the system is installed. : SYSTEM - Provides a means for you to log in with full privileges. The SYSTEM record can be modified but cannot be renamed or deleted from the UAF. CAUTION: Do not change the SYSTEM account UAF record fields for the default device and directory, and privileges. Installation of VMS maintenance releases and optional software products depends on certain values in these fields. : SYSTEST - Provides an appropriate environment for running the User Environment Test Package (UETP). The SYSTEST record should be disabled once the system is installed. 4.1.2 GENERAL MAINTENANCE OF THE UAF Usually, you use the UAF supplied with the distribution kit. (You can, however, rename the UAF with the DCL command RENAME, and then create a new UAF with AUTHORIZE.) You should limit any kind of access to this file to the SYSTEM account. Furthermore, each time you modify the file, create a backup copy so that in case of a system failure you do not lost the modifications. See Chapter 8 for procedures for backing up files. The UAF is access as a shared file, and updates to the UAF are made on a per record basis, which eliminates the need for both a temporary UAF and a new version of the UAF after each AUTHORIZE session. Updates become effective as soon as AUTHORIZE commands are entered, not after the termination of AUTHORIZE. (For this reason, you should not enter temporary values with the intent of fixing them later in the session.) After installing the system, you should make the following modifications to the UAF: : SYSTEM, FIELD, & SYSTEST ACCOUNTS: If the passwords on these accounts are not secure or if they have not been changed recently, be sure to change the passwords. Use obscure passwords of six characters or more and continue to change them on a regular basis. You should not permit general users access to these accounts. In addition to changing the password, you can disable an account, especially if it is used infrequently. To disable an account, specify the following AUTHORIZE command: UAF> MODIFY username /FLAGS=DISUSER The login flag DISUSER disables the account and prevents anyone from logging into the account. To enable the account when it is needed, run AUTHORIZE and specify MODIFY users /FLAGS=NODISUSER. However, you should be cautious about disabling the SYSTEM account, because some optional software and some command procedures may not start up properly if the SYSTEM account is disabled. CAUTION: Be careful not to disable all of your privileged system accounts. If you inadvertently do so, you can recover by setting the UAFALTERNATE SYSGEN parameter during a conversational bootstrap operation. See Chapter 2 for information on emergency startup procedures. : DEFAULT ACCOUNT: You may want to change several fields in this account. For example: UAF> MODIFY DEFAULT/DEVICE=DISK$USER/WSQUO=750 The default device is set to the name most commonly used for user accounts that will be added. Likewise the working set value is set to a value appropriate for most users on the system. Use the SYSTEM account only for system functions such as performing backups and installing maintenance updates. The account comes to you with full privileges, so exercise caution in using it. For example, because you have BYPASS privilege. the system will allow you to delete any file no matter what its protection. If you type an incorrect name or spurious asterisk, you may destroy files that you or other users need to keep. For this reason, use another account with fewer privileges for day-to-day system management activities. If you want to receive mail sent to the system account, use the SET FORWARD command in the MAIL Utility to have any SYSTEM mail forwarded to any other account. To use the SET FORWARD command for this purpose, do the following: 1. Make sure that you are logged in to the SYSTEM account. 2. Enter the MAIL Utility by entering the MAIL command at DCL Level. 3. At the MAIL> prompt, enter the command SET FORWARD username. 4.2 ADDING A USER ACCOUNT How you set up a user account depends on the needs of the individual user. In general, there are two types of accounts: : INTERACTIVE: A person using an interactive account has access to the system software and can perform work of a general nature (program development, text editing, and so on). Usually, such an account is considered individual; that is, only one person can use it. : CAPTIVE: A person using a captive account (also called a turnkey or application account) has access only to limited user software and can only perform work that is limited to a particular function. Access to a captive account is limited by function; that is, only those who perform a particular function can use it. For example, you might develop an inventory system. Anyone whose job entails inventory control can access your system, but that person cannot access other subsystems or the base software. You should perform the following tasks in conjunction with adding a user account: 1. Determine a user name and password. 2. Determine a unique user identification code (UIC). 3. Decide where the account's files will reside (the device and directory). 4. Create a default directory on the appropriate volume, using the following DCL command: $ CREATE/DIRECTORY directory-spec/OWNER_UIC= uic 5. Determine the security needs of the account (that is, the level of file protection, privileges, and access control). Once you analyze the purpose of a user account and decide which attributes and resources it requires, you can use the Authorize Utility to create the account. Give yourself the SYSPRV privilege. Then enter the following commands to set your default device and directory to that of SYS$SYSTEM and invoke the utility as follows: $ SET DEFAULT SYS$SYSTEM $ RUN AUTHORIZE When the utility responds with the UAF> prompt, use the AUTHORIZE command ADD to specify attributes in the UAF fields as shown in this example: UAF> ADD JONES/PASSWORD=LPB57WN/UIC=[014,1] - _UAF> /DEVICE=DISK$USER/DIRECTORY=[JONES] - _UAF> /LGICMD=DISK$USER: [NEWPROD]GRPLOGIN - _UAF> /OWNER="ROBERT JONES"/ACCOUNT=DOC The /OWNER and /ACCOUNT entries are primarily for accounting purposes and can be omitted unless required by your site. The following unspecified qualifiers usually take their default values from the DEFAULT record: : LIMITES and QUOTAS - (/ASTLM, /BIOLM, /CPUTIME, /DIOLM, ENQLM, /FILLM, /]TQUOTA, /MAXACCTJOBX, /MAXDETACH, /MAXJOBS, /PGFLQUOTA, /PRCLM, /SHRFILLM, /TQELM, /WSDEFAULT, /WSEXTENT, /WSQUOTA) - These qualifiers impose limits on the use of resuable system resources; the default values are adequate in most cases. : PRIORITY - (/PRIORITY, /QUEPRIORITY) - The default values are usually adequate for accounts not running real-time processes. : PRIVILEGES - (/DEFPRIVILEGES, /PRIVILEGES) - The default privileges (TMPMBX, NETMBX) are usually adequate, depending on the purpose of the account. : PRIMARY & SECONDARY LOGIN TIMES; LOGIN FUNCTIONS - (/ACCESS, /DIALUP, /FLAG, /INTERACTIVE, /LOCAL, /PRIMEDAYS, /REMOTE) - By default, users are allowed to log in at any hour of any day. To override the setting of a particular day, use the DCL command SET DAY. Use this command if a holiday occurs on a day that would normally be treated as a primary day and you want it treated as a secondary day. The following example shows an AUTHORIZE command that adds a UAF record of a captive account: UAF> ADD INVENTORY/PASSWORD=QRC7Y94A/UIC=[033,066] - _UAF> /DEVICE=DISK$INVENT/DIRECTORY[INV]/LGICMD=INVENTORY - _UAF> /FLAGS=CAPTIVE/NOACCESS=(PRIMARY, 18-8,SECONDARY, 0-23) In this example, the /FLAGS and /NOACCESS qualifiers restrict users from logging in to the captive account. The /NOACCESS qualifier limits logins to specific hours. The /FLAGS=CAPTIVE qualifier adds the login flag CAPTIVE to the captive account record. The CAPTIVE flag locks the person using the account into the application software by doing the following: : Disabling the CTRL/Y function to prevent users from interrupting the execution of the command procedure and gaining access to the command interpreter : Preventing the user from specifying an alternate command interpreter with the /CLI qualifier at login time : Preventing the user from specifying an alternate default disk device with the /DISK qualifier at login time The following examples summarize the steps for setting up an individual user account and a captive account: $ SET DEFAULT SYS$SYSTEM $ $ RUN AUTHORIZE UAF>ADD JONES - ! User name _/PASSWORD=ROCKET - ! Password _/UIC=[014,1] - ! UIC _/ACCOUNT=DOC - ! Accounting Group Name _/OWNER="ROCKET JONES" ! Owner _/DEVICE=$DISK1 - ! Default directory _/DIRECTORY=[JONES] UAF>EXIT $ $ ! Create top-level directory for individual $ CREATE/DIRECTORY $DISK1: [JONES] - _$ /OWNER_UIC=[DOC,JONES] - _$ /PROTECTION=(S:RWE,0:RWE,G:RE,W:RE) $ 4.3 SETTING UP A CAPTIVE ACCOUNT WITH AUTHORIZE You use the automatic login facility (ALFMAINT) to set up a terminal that accepts automatic logins from authorized users. For example, a terminal might be set up for the account INVENTORY, which automatically logs a user into a captive account when INVENTORY is specified as the user name. First, you must follow the steps described in the previous sections to create the toplevel default directory and add the account. Once the account has been added, you set your default directory to SYS$MANAGER and invoke the ALFMAINT command procedure. ALFMAINT prompts you for the name of the terminal that you want assciated w/ the user name of the automatic login account. The following example summarizes the steps for setting up automatic logins for an individual user account and a captive account: INDIVIDUAL ACCOUNT W/ AUTOMATIC LOGIN $ SET DEFAULT SYS$SYTEM $ $ RUN AUTHORIZE UAF>ADD JONES - ! Username _/PASSWORD= - ! Null password _/UIC=[014,1] - ! UIC _/ACCOUNT=DOC! ! Accounting group name _/OWNER="ROCKET JONES" - ! Owner _/DEVICE=$DISK1 - ! Default directory _/DIRECTORY=[JONES] - UAF>EXIT $ $ ! Create top-level directory for individual $ CREATE/DIRECTORY $DISK1: [JONES] - _$/OWNER_UIC=[DOC,JONES] _$/PROTECTION=(S:RWE, O:RWE, G:RE, W:RE) $ $ SET DEFAULT SYS$MANAGER $ $ @ALFMAINT Enter the name of the terminal thatt you would like to set for automatic login, or a blank line or EXIT to exit. terminal (ddcu)? TTA1 ! Assigned terminal Username? JONES Terminal (ddcu)? EXIT CAPTIVE ACCOUNT W/ AUTOMATIC LOGIN $ SET DEFAULT SYS$SYSTEM $ $ RUN AUTHORIZE UAF>ADD INVENTORY - ! Username _/PASSWORD= - ! Null password _/UIC=[033,066] - ! UIC _/ACCOUNT=INV - ! Accounting group name _/LGICMD=$DISK1:[INVENTORY]LOGIN ! Login File _/ACCESS=(PRIMARY,8-17) - ! No off hours _/FLAGS=CAPTIVE ! All flags on UAF>EXIT $ $ SET DEFAULT SYS$MANAGER $ @ALFMAINT Enter the name of the terminal that you would like to set for automatic login, or a blank line or EXIT to exit. Terminal (ddcu)? TTA0 ! All terminals Username? INVENTORY ! on automatic Terminal (ddcu)? TTA1 ! login except Username? INVENTORY ! the console terminal Terminal (ddcu)? TTA2 ! (the console terminal Username? INVENTORY ! for this system is TTA4) Terminal (ddcu)? TTA3 Username? INVENTORY Terminal (ddcu)? EXIT 4.4 MODIFYING A USER ACCOUNT Use the AUTHORIZE command MODIFY to change any of the fields in an existing, user account. For exmple, the following command is used to change user WELCH's password: UAF> MODIFY WELCH/PASSWORD=newpassword 4.5 LISTING USER ACCOUNTS Use the AUTHORIZE command LIST to create the file SYSUAF.LIS containing a summary of all user records in the UAF, as follows: UAF> LIST %UAF-I-LISTMSG1, writing listing file %UAF-I-LISTMSG2, listing file SYSUAF.LIS complete By default, the LIST command produces a brief report conatining the following information from the UAF: : ACCOUNT OWNER : USER NAME : UIC : ACCOUNT NAMES : PRIVILEGES : PROCESS PRIORITY : DEFAULT DISK AND DIRECTORY Use the /FULL qualifier to create a full report of all the information contained w/in the UAF, as follows: UAF> LIST/FULL %UAF-I-LISTMSG1, writing listing file %UAF-I-LISTMSG2, listing file SYSUAF.LIST complete 4.6 DELETEING A USER ACCOUNT The main problem in deleting an account, especially an interactive account is cleaning up the files used by the account. The following steps are suggested: 1. Copy (or have the outgoing user of the account copy) any files of value to the ownership of another account. Be sure to change the owner UIC of the files to match the owner UIC of the new owner. You can also use the Backup Utility ( BACKUP ) to copy the files to a backup tape or disk. 2. Change the password, and log in to the account that you want to delete. ( By working from a nonprivileged account, you can avoid inadvertently deleting files that may be owned by an account other than the one that you want to delete.) 3. Delete the account's files and directories from the deepest level up to the to level using the following procedure: a. Locate and examine all subdirectories using the DCL command DRECTORY [default ... ], where default is the name of the account's default directory. b. Delete the files in each subdirectory and then delete the subdirectory. Note that directory files are protected against owner deleteion, therefore, you must change the protection before deleting directory files. c. Delete the account's top-level directory. Example 4-2 Illustrates a command procedure that deletes an account's files from the bottom level up. NOTE: the command procedure in Example 4-2 should not be executed from a privileged account. 4. Remove the account, using the Authorize Utility. 5. Remove the user's disk quota entry from the disk quota file, if one existed, w/ the SYSMAN UTILITY. 6. Remove associated VAXmail information by entering the MAIL command REMOVE username. EXAMPLE 4-2: COMMAND PROCEDURE TEMPLATE FOR DELETING AN ACCOUNT'S FILES $ ! DELTREE.COM -- Deletes a complete directory tree $ ! P1 = pathname of root of tree to delete $ ! All files and directories in the tree, including $ ! the named root, are deleted. $ ! $ IF "'DELTREE'" .EQS. "" THEN DELTREE = "@SYS$LIBRARY:DELTREE" $ ON CONTROL_Y THEN GOTO DONE $ ON WARNING THEN GOTO DONE $ DEFAULT = F$LOGICAL ("SYS$DISK" + F$DIRECTORY () $10: $ IF P1 .NES. "" THEN GOTO 20 $ INQUIRE P1 "ROOT" $ GOTO 10 $20: $ IF F$PARSE(P1) .EQS. "" THEN OPEN FILE 'P1' $ SET DEFAULT 'P1' $LOOP: $ FILESPEC = F$SEARCH("*.DIR;1") $ IF FILESPEC .EQS. "" THEN GOTO LOOPEND $ DELTREE [.'F$PARSE(FILESPEC..."NAME")'] $ GOTO LOOP $LOOPEND: $ IF F$SEARCH(+*.*;*") .NES. "" THEN DELETE *.*;* $ DIR = (F$DIRECTORY()-"]"-">")-F$PARSE("[-]"...- "DIRECTORY")-"]"-">")-"."-"["-"<" $ SET PROTECTION=WORLD:RWED [-]'DIR'.DIR;1 $ DELETE [-]'DIR'.DIR;1 $DONE: $ SET DEFAULT 'DEFAULT' If you never assign multiple users the same UIC, you can use the Backup Utility to remove the user's files, even if the files are scattered throughout the directory structure. The following is an example of a BACKUP command used to remove files. $ BACKUP/DELETE PUBLIC:[...]/OWNER=[21,103] MTAO:PUBLICUIC.SAV This BACKUP command copies and deletes only those files owned by the specified UIC on disk PUBLIC. The files are copied into a save set named PUBLICUIC on device MTA0. Note that the BACKUP/DELETE command does not delete the directory files (file extension DIR) for the account. DISABLING A USER ACCOUNT If you want to disable an account w/out deleting it, set the disable user flag (/FLAGS=DISUSER) using AUTHORIZE. If the user is logged in, the account is diabled only after the user logs out. Disabling a powerful yet infrequently used account provides an extra security mesasure by eliminating the risk of guessed or stolen passwords. $EOF [OTHER WORLD BBS]