CPSA UNIX SECURITY ASSESSMENT | 2025/2026
UPDATE | ACTUAL QUESTIONS AND ANSWERS | WITH
COMPLETE SOLUTION
What R* services can be used for user enumeration? Answer - rusers, rwho.
What does rwho do? Answer - Reports information on logged on users on a
remote host.
What does rwho do? Answer - Reports all users logged onto machines in the
local network.
How can users be enumerated with SMTP? Answer - VRFY or RCPT TO
command.
What does finger do? Answer - Finger is a program that can be used to find
information about users of a system. It usually lists the login name, the full
name, and possibly other details about the user you are fingering. This is a
dated service that was used to determine who was currently on a device. Gets
it information from /etc/passwd.
What ports are used for FTP and for what reasons? Answer - 20 - data and 21 -
command
What kind of access allows any users to interact with an FTP service? Answer -
Anonymous
, What could be risk of allowing anyone to write to FTP service? Answer -
Potential upload into code execution, obtaining sensitive files, identifying
vulnerable version.
What is a mail relay? Answer - SMTP relay lets users send e-mails through
external servers. Spammers and hackers can use an e-mail server to send spam
or malware through e-mail under the guise of the unsuspecting open-relay
owner.
What is CVE-2003-0694? Answer - The prescan function in Sendmail 8.12.9
allows remote attackers to execute arbitrary code via buffer overflow attacks.
What is CVE-2003-0161? Answer - A buffer overflow has been reported in the
prescan() function of Sendmail versions 8.12.9 and earlier. The overflow can be
exploited to execute arbitrary code on the system.
What is CVE-2002-1337? Answer - Buffer overflow in Sendmail 5.79 to 8.12.7
allows remote attackers to execute arbitrary code via certain formatted address
fields, related to sender and recipient header comments as processed by the
crackaddr function of headers.c.
What is NFS? Answer - NFS is Network File System, a legacy protocol providing
network based file services. Allowing files to be accessed as they would be
locally.
How can NFS be restricted? Answer - The etcexports file can be altered to add
a policy restricting access to certain hosts or directories. The SUID bit can be
disabled too.
UPDATE | ACTUAL QUESTIONS AND ANSWERS | WITH
COMPLETE SOLUTION
What R* services can be used for user enumeration? Answer - rusers, rwho.
What does rwho do? Answer - Reports information on logged on users on a
remote host.
What does rwho do? Answer - Reports all users logged onto machines in the
local network.
How can users be enumerated with SMTP? Answer - VRFY or RCPT TO
command.
What does finger do? Answer - Finger is a program that can be used to find
information about users of a system. It usually lists the login name, the full
name, and possibly other details about the user you are fingering. This is a
dated service that was used to determine who was currently on a device. Gets
it information from /etc/passwd.
What ports are used for FTP and for what reasons? Answer - 20 - data and 21 -
command
What kind of access allows any users to interact with an FTP service? Answer -
Anonymous
, What could be risk of allowing anyone to write to FTP service? Answer -
Potential upload into code execution, obtaining sensitive files, identifying
vulnerable version.
What is a mail relay? Answer - SMTP relay lets users send e-mails through
external servers. Spammers and hackers can use an e-mail server to send spam
or malware through e-mail under the guise of the unsuspecting open-relay
owner.
What is CVE-2003-0694? Answer - The prescan function in Sendmail 8.12.9
allows remote attackers to execute arbitrary code via buffer overflow attacks.
What is CVE-2003-0161? Answer - A buffer overflow has been reported in the
prescan() function of Sendmail versions 8.12.9 and earlier. The overflow can be
exploited to execute arbitrary code on the system.
What is CVE-2002-1337? Answer - Buffer overflow in Sendmail 5.79 to 8.12.7
allows remote attackers to execute arbitrary code via certain formatted address
fields, related to sender and recipient header comments as processed by the
crackaddr function of headers.c.
What is NFS? Answer - NFS is Network File System, a legacy protocol providing
network based file services. Allowing files to be accessed as they would be
locally.
How can NFS be restricted? Answer - The etcexports file can be altered to add
a policy restricting access to certain hosts or directories. The SUID bit can be
disabled too.
