ISC2 SSCP Systems Security Certified Practitioner Exam Practice Test

Answer : A

XSS or Cross-Site Scripting is a threat to web applications where malicious code is placed on a website that attacks the use using their existing authenticated session status.

Cross-Site Scripting attacks are a type of injection problem, in which malicious scripts are injected into the otherwise benign and trusted web sites. Cross-site scripting (XSS) attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user. Flaws that allow these attacks to succeed are quite widespread and occur anywhere a web application uses input from a user in the output it generates without validating or encoding it.

An attacker can use XSS to send a malicious script to an unsuspecting user. The end user's browser has no way to know that the script should not be trusted, and will execute the script. Because it thinks the script came from a trusted source, the malicious script can access any cookies, session tokens, or other sensitive information retained by your browser and used with that site. These scripts can even rewrite the content of the HTML page.

Mitigation:

Configure your IPS - Intrusion Prevention System to detect and suppress this traffic.

Input Validation on the web application to normalize inputted data.

Set web apps to bind session cookies to the IP Address of the legitimate user and only permit that IP Address to use that cookie.

See the XSS (Cross Site Scripting) Prevention Cheat Sheet

See the Abridged XSS Prevention Cheat Sheet

See the DOM based XSS Prevention Cheat Sheet

See the OWASP Development Guide article on Phishing.

See the OWASP Development Guide article on Data Validation.

The following answers are incorrect:

Intrusion Detection Systems: Sorry. IDS Systems aren't usually the target of XSS attacks but a properly-configured IDS/IPS can 'detect and report on malicious string and suppress the TCP connection in an attempt to mitigate the threat.

Firewalls: Sorry. Firewalls aren't usually the target of XSS attacks.

DNS Servers: Same as above, DNS Servers aren't usually targeted in XSS attacks but they play a key role in the domain name resolution in the XSS attack process.

The following reference(s) was used to create this question:

CCCure Holistic Security+ CBT and Curriculum

and

https://www.owasp.org/index.php/Cross-site_Scripting_%28XSS%29

Answer : A

The Simple Network Management Protocol (SNMP) is a useful tool for remotely managing network devices.

Since it can be used to reconfigure devices, SNMP traffic should be blocked at the organization's firewall.

Using a VPN with encryption or some type of Tunneling software would be highly recommended in this case.

Source: STREBE, Matthew and PERKINS, Charles, Firewalls 24seven, Sybex 2000, Chapter 4: Sockets and Services from a Security Viewpoint.

Answer : A

The greatest danger from BootP or DHCP (Dynamic Host Control Protocol) is from an intruder on the network impersonating a DHCP server and thereby misconfiguring the DHCP clients. Other choices are possible consequences of DHCP impersonation.

Source: STREBE, Matthew and PERKINS, Charles, Firewalls 24seven, Sybex 2000, Chapter 4: Sockets and Services from a Security Viewpoint.

Answer : B

BootP was developed as a simple mechanism for allowing simple network terminals to load their operating system from a server over the LAN. Over time, it has expanded to allow centralized configuration of many aspects of a host's identity and behavior on the network. Note that DHCP, more complex, has replaced BootP over time.

Source: STREBE, Matthew and PERKINS, Charles, Firewalls 24seven, Sybex 2000, Chapter 4: Sockets and Services from a Security Viewpoint.

Answer : B

A routing table is used when a destination IP address is not located on the current LAN segment. It consists of a list of station and network addresses and a corresponding gateway IP address further along to which a routing equipment should send packets that match that station or network address. A list of IP addresses and corresponding MAC addresses is an ARP table. A DNS is used to match host names and corresponding IP addresses. The last choice is a distracter.

Source: STREBE, Matthew and PERKINS, Charles, Firewalls 24seven, Sybex 2000, Chapter 3: TCP/IP from a Security Viewpoint.

Answer : B

IPSec can be run in either tunnel mode or transport mode. Each of these modes has its own particular uses and care should be taken to ensure that the correct one is selected for the solution:

Tunnel mode is most commonly used between gateways, or at an end-station to a gateway, the gateway acting as a proxy for the hosts behind it.

Transport mode is used between end-stations or between an end-station and a gateway, if the gateway is being treated as a host---for example, an encrypted Telnet session from a workstation to a router, in which the router is the actual destination.

As Figure 1 shows, basically transport mode should be used for end-to-end sessions and tunnel mode should be used for everything else. (Refer to the figure for the following discussion.)

Figure 1 Tunnel and transport modes in IPSec.

Figure 1 displays some examples of when to use tunnel versus transport mode:

Tunnel mode is most commonly used to encrypt traffic between secure IPSec gateways, such as between the Cisco router and PIX Firewall (as shown in example A in Figure 1). The IPSec gateways proxy IPSec for the devices behind them, such as Alice's PC and the HR servers in Figure 1. In example A, Alice connects to the HR servers securely through the IPSec tunnel set up between the gateways.

Tunnel mode is also used to connect an end-station running IPSec software, such as the Cisco Secure VPN Client, to an IPSec gateway, as shown in example B.

In example C, tunnel mode is used to set up an IPSec tunnel between the Cisco router and a server running IPSec software. Note that Cisco IOS software and the PIX Firewall sets tunnel mode as the default IPSec mode.

Transport mode is used between end-stations supporting IPSec, or between an end-station and a gateway, if the gateway is being treated as a host. In example D, transport mode is used to set up an encrypted Telnet session from Alice's PC running Cisco Secure VPN Client software to terminate at the PIX Firewall, enabling Alice to remotely configure the PIX Firewall securely.

AH Tunnel Versus Transport Mode

Figure 2 shows the differences that the IPSec mode makes to AH. In transport mode, AH services protect the external IP header along with the data payload. AH services protect all the fields in the header that don't change in transport. The header goes after the IP header and before the ESP header, if present, and other higher-layer protocols.

In tunnel mode, the entire original header is authenticated, a new IP header is built, and the new IP header is protected in the same way as the IP header in transport mode.

Figure 2 AH tunnel versus transport mode.

AH is incompatible with Network Address Translation (NAT) because NAT changes the source IP address, which breaks the AH header and causes the packets to be rejected by the IPSec peer.

ESP Tunnel Versus Transport Mode

Figure 3 shows the differences that the IPSec mode makes to ESP. In transport mode, the IP payload is encrypted and the original headers are left intact. The ESP header is inserted after the IP header and before the upper-layer protocol header. The upper-layer protocols are encrypted and authenticated along with the ESP header. ESP doesn't authenticate the IP header itself.

NOTE

Higher-layer information is not available because it's part of the encrypted payload.

When ESP is used in tunnel mode, the original IP header is well protected because the entire original IP datagram is encrypted. With an ESP authentication mechanism, the original IP datagram and the ESP header are included; however, the new IP header is not included in the authentication.

When both authentication and encryption are selected, encryption is performed first, before authentication. One reason for this order of processing is that it facilitates rapid detection and rejection of replayed or bogus packets by the receiving node. Prior to decrypting the packet, the receiver can detect the problem and potentially reduce the impact of denial-of-service attacks.

Figure 3 ESP tunnel versus transport mode.

ESP can also provide packet authentication with an optional field for authentication. Cisco IOS software and the PIX Firewall refer to this service as ESP hashed message authentication code (HMAC). Authentication is calculated after the encryption is done. The current IPSec standard specifies SHA-1 and MD5 as the mandatory HMAC algorithms.

The main difference between the authentication provided by ESP and AH is the extent of the coverage. Specifically, ESP doesn't protect any IP header fields unless those fields are encapsulated by ESP (tunnel mode). Figure 4 illustrates the fields protected by ESP HMAC.

Figure 4 ESP encryption with a keyed HMAC.

IPSec Transforms

An IPSec transform specifies a single IPSec security protocol (either AH or ESP) with its corresponding security algorithms and mode. Example transforms include the following:

The AH protocol with the HMAC with MD5 authentication algorithm in tunnel mode is used for authentication.

The ESP protocol with the triple DES (3DES) encryption algorithm in transport mode is used for confidentiality of data.

The ESP protocol with the 56-bit DES encryption algorithm and the HMAC with SHA-1 authentication algorithm in tunnel mode is used for authentication and confidentiality.

Transform Sets

A transform set is a combination of individual IPSec transforms designed to enact a specific security policy for traffic. During the ISAKMP IPSec security association negotiation that occurs in IKE phase 2 quick mode, the peers agree to use a particular transform set for protecting a particular data flow. Transform sets combine the following IPSec factors:

Mechanism for payload authentication---AH transform

Mechanism for payload encryption---ESP transform

IPSec mode (transport versus tunnel)

Transform sets equal a combination of an AH transform, plus an ESP transform, plus the IPSec mode (either tunnel or transport mode).

This brings us to the end of the second part of this five-part series of articles covering IPSec. Be sure to catch the next installment.

Cisco Press at: http://www.ciscopress.com/articles/printerfriendly.asp?p=25477

and

Source: TIPTON, Harold F. & KRAUSE, MICKI, Information Security Management Handbook, 4th Edition, Volume 2, 2001, CRC Press, NY, Pages 166-167.

Answer : A

Source: TIPTON, Harold F. & KRAUSE, MICKI, Information Security Management Handbook, 4th Edition, Volume 2, 2001, CRC Press, NY, page 164.