Compromised software updates

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. A criminal hides malicious code inside a real update from a trusted software supplier. What is this called?

A A compromised software update

B A normal security patch

2. Why do users install a compromised update without worry?

A It appears to come from a supplier they already trust

B It always asks them to disable their antivirus

3. Where does the malicious code get added in a compromised software update?

A Into the supplier's update before it reaches users

B Only onto the user's device after installing

4. A program has automatic updates switched on. A compromised update is released. What could happen?

A The update waits until the user approves each line of code

B The malicious update may install on many devices without the user choosing it

5. Which statement is true?

A Anything from a trusted supplier is always safe

B An update can be dangerous even when it comes from a trusted supplier

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1update_server.upload("app_v2.1.exe") # contains hidden malware		AA criminal slips malicious code into a genuine update on the supplier's own server, so it looks like normal software.
2auto_update = True # installs without asking		BBelieving automatic updates remove all risk. A compromised update installs automatically, giving malware a quick route onto many devices.
3Users trust an update because it comes from a supplier they already use and believe is safe.		CUpdates install by themselves, so a compromised update can reach many devices before anyone notices the problem.
4A safer approach is to check that an update is genuine before installing it, rather than trusting its source alone.		Dif verify_signature(update): install(update)
5if source == "trusted": install(update) # so it must be safe		EAssuming an update is safe just because it comes from a trusted supplier. The supplier's system may have been compromised.
6auto_update = True # no need to ever check updates		Fif sender == "trusted_supplier": install(update)

Definitions

compromised software update

Fill in the Blanks

Complete each line of code by filling in the missing parts.

supplier = "trusted" autoUpdate = ____

if supplier __ "trusted": install(update)

infected = True if ________: alert("Do not install")

trusted = True infected = True safe = trusted ___ not infected

updates = ["v2.1", "v2.2"] for update in _______: verify(update)

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A update = download(supplier)

B if not is_signed(update):

C install(update)

D else:

E block(update)

Question 2

A supplier = 'TrustSoft'

B update = get_update(supplier)

C if supplier = 'TrustSoft':

D install(update)

Question 3

A auto_update = True

B while auto_update:

C update == check_server()

D verify(update)

Question 4

A update = download(supplier)

B hash = sha256(update)

C if hash == published_hash:

D block(update)

E else:

F alert_user()

Question 5

A def install_update(update)

B if update.is_signed:

C run(update)

D return 'done'

Answer Key

Compromised software updates

Section A: Quick Questions

A — A compromised software update

A — It appears to come from a supplier they already trust

A — Into the supplier's update before it reaches users

B — The malicious update may install on many devices without the user choosing it

B — An update can be dangerous even when it comes from a trusted supplier

Section B: Match the Pairs

update_server.upload("app_v2.1.exe") # contains hidden malware → A criminal slips malicious code into a genuine update on the supplier's own server, so it looks like normal software.

auto_update = True # installs without asking → Updates install by themselves, so a compromised update can reach many devices before anyone notices the problem.

Users trust an update because it comes from a supplier they already use and believe is safe. → if sender == "trusted_supplier": install(update)

A safer approach is to check that an update is genuine before installing it, rather than trusting its source alone. → if verify_signature(update): install(update)

if source == "trusted": install(update) # so it must be safe → Assuming an update is safe just because it comes from a trusted supplier. The supplier's system may have been compromised.

auto_update = True # no need to ever check updates → Believing automatic updates remove all risk. A compromised update installs automatically, giving malware a quick route onto many devices.

Section C: Definitions

compromised software update — A software update from a trusted supplier that criminals have secretly infected with malicious code, so users install it believing it is safe.

Section D: Fill in the Blanks

supplier = "trusted"
autoUpdate = True

if supplier == "trusted":
    install(update)

infected = True
if infected:
    alert("Do not install")

trusted = True
infected = True
safe = trusted and not infected

updates = ["v2.1", "v2.2"]
for update in updates:
    verify(update)

Section E: Spot the Error

B — The check is reversed. This would install updates that are NOT signed and block the signed ones. It should be 'if is_signed(update):' so only verified updates are installed.

C — A single = assigns a value, and it can't be used as a condition. To compare the supplier name you need the == operator.

C — The == operator compares values, so the update is never stored. Use a single = to assign the result of check_server() to update before verifying it.

D — When the hash matches the supplier's published hash, the update is the genuine file and should be installed. Blocking it is the wrong action. The line should be install(update).

A — A function definition must end with a colon. The line should be 'def install_update(update):'.