1. What is XDR?
XDR (Extended Detection and Response) is a cybersecurity approach that unifies protection across multiple layers.
Unlike traditional tools that operate in silos (each working independently), XDR automatically collects and correlates data from multiple security levels:
– Endpoints (computers, servers)
– Network (data flows)
– Cloud and virtual infrastructures
– Email systems
2. Quishing: A Classic Use Case for XDR
Let’s revisit the previous threat. Quishing is particularly difficult to detect because it uses an out-of-band vector (the user’s smartphone).
Without XDR:
The computer’s antivirus sees nothing. The firewall only observes a normal HTTPS connection. The attack succeeds.
With XDR:
The solution detects that a user received a suspicious email, scanned a QR code (mobile telemetry), and at the same time an unusual login attempt occurs on their Office 365 account. XDR links these isolated events and blocks access.
Real Case Study: The “SolarWinds” (Nobelium) Attack
This is one of the clearest examples justifying XDR. In 2020, elite hackers (the Nobelium group) infiltrated SolarWinds’ servers to corrupt a software update used by thousands of companies and government agencies.
Why traditional tools failed:
– EDR alone: Detected nothing because the malicious code was signed with a legitimate certificate. The antivirus considered it safe.
– Firewall alone: Saw outbound traffic to cloud servers (AWS/Azure), which was normal for a software update.
How XDR could have changed the outcome:
In an infrastructure equipped with a strong XDR:
– Signal 1 (Identity): An admin account creates unusual SAML access tokens.
– Signal 2 (Process): SolarWinds software sends a network command to an IP unknown to its reputation database.
Role of XDR:
Instead of treating these two alerts as minor and separate, XDR correlates them. It detects lateral movement and instantly blocks the compromised access tokens, stopping data exfiltration before it becomes critical.
3. Quishing + XDR: Defense Against Social Engineering
As seen with Quishing, attackers try to bypass corporate security using an employee’s personal or work smartphone.
XDR is the only solution capable of detecting that:
– An email containing an image (QR Code) arrives in an Outlook mailbox.
-Minutes later, a mobile device registered in MDM (Mobile Device Management) connects to a phishing domain.
– An MFA (Multi-Factor Authentication) login attempt is approved from an unusual geographic location.
XDR’s verdict: It identifies a Quishing attack and forces all active user sessions to log out.
4. Advanced Terms for Professionals (Glossary)
– Raw telemetry: Unfiltered data sent by all sensors to the XDR data lake.
– indicators of Compromise (IoC): Digital traces (IPs, file signatures) left by attackers.
– Indicators of Attack (IoA): Behavioral analysis (e.g., why is a server querying the employee directory at 4 a.m.?).
– Dwell Time: The time an attacker spends inside a network before detection. XDR aims to reduce this from months to minutes.
5. Existing Tools
– Native XDR: All tools come from the same vendor (e.g., Microsoft, Palo Alto). Easier integration.
– Open XDR: Connects your existing multi-vendor tools to a central platform. More flexible.
Sources & References
– (Gartner: Reports on XDR market evolution)
– (ANSSI: Recommendations on incident detection)
– (The Guardian / Cybermalveillance.gouv.fr for Quishing cases)
– (Microsoft Threat Protection Nobelium/SolarWinds report)