Detailed attack pattern

Draft

CAPEC-102: Session Sidejacking

Session sidejacking takes advantage of an unencrypted communication channel between a victim and target system. The attacker sniffs traffic on a network looking for session tokens in unencrypted traffic. Once a session token is captured, the attacker performs malicious actions by using the stolen token with the targeted application to impersonate the victim. This attack is a specific method of session hijacking, which is exploiting a valid session token to gain unauthorized access to a target system or information. Other methods to perform a session hijacking are session fixation, cross-site scripting, or compromising a user or server machine and stealing the session token.

Last updated June 1, 2026

High

Typical severity

Per MITRE

High

Likelihood of attack

Per MITRE

5

Related weaknesses

CWEs this targets

Detailed

Abstraction

MITRE classification

Overview

CAPEC-102 (Session Sidejacking) is a detailed-level attack pattern catalogued by MITRE in the Common Attack Pattern Enumeration and Classification (CAPEC). It describes a recurring method attackers use to exploit software weaknesses.

How the attack works

The phases an attacker typically follows to carry out this attack.

Step 1
Explore
[Detect Unprotected Session Token Transfer] The attacker sniffs on the wireless network to detect unencrypted traffic that contains session tokens.
- The attacker uses a network sniffer tool like ferret or hamster to monitor the wireless traffic at a WiFi hotspot while examining it for evidence of transmittal of session tokens in unencrypted or recognizably encrypted form. An attacker applies their knowledge of the manner by which session tokens are generated and transmitted by various target systems to identify the session tokens.
Step 2
Experiment
[Capture session token] The attacker uses sniffing tools to capture a session token from traffic.
Step 3
Experiment
[Insert captured session token] The attacker attempts to insert a captured session token into communication with the targeted application to confirm viability for exploitation.
Step 4
Exploit
[Session Token Exploitation] The attacker leverages the captured session token to interact with the targeted application in a malicious fashion, impersonating the victim.

What the attacker needs

Prerequisites

An attacker and the victim are both using the same WiFi network.
The victim has an active session with a target system.
The victim is not using a secure channel to communicate with the target system (e.g. SSL, VPN, etc.)
The victim initiated communication with a target system that requires transfer of the session token or the target application uses AJAX and thereby periodically "rings home" asynchronously using the session token

Skills required

Low skill: Easy to use tools exist to automate this attack.

Resources required

A packet sniffing tool, such as wireshark, can be used to capture session information.

Consequences

What a successful CAPEC-102 attack can achieve.

Gain Privileges

Affects: Confidentiality, Access Control, Authorization

Modify Data

Affects: Integrity

Read Data

Affects: Confidentiality

Unreliable Execution

Affects: Availability

How to mitigate it

Defenses that reduce the risk of CAPEC-102.

Make sure that HTTPS is used to communicate with the target system. Alternatively, use VPN if possible. It is important to ensure that all communication between the client and the server happens via an encrypted secure channel.
Modify the session token with each transmission and protect it with cryptography. Add the idea of request sequencing that gives the server an ability to detect replay attacks.

Examples

The attacker and the victim are using the same WiFi public hotspot. When the victim connects to the hotspot, they has a hosted e-mail account open. This e-mail account uses AJAX on the client side which periodically asynchronously connects to the server side and transfers, amongst other things, the user's session token to the server. The communication is supposed to happen over HTTPS. However, the configuration in the public hotspot initially disallows the HTTPS connection (or any other connection) between the victim and the hosted e-mail servers because the victim first needs to register with the hotspot. The victim does so, but their e-mail client already defaulted to using a connection without HTTPS, since it was denied access the first time. Victim's session token is now flowing unencrypted between the victim's browser and the hosted e-mail servers. The attacker leverages this opportunity to capture the session token and gain access to the victim's hosted e-mail account.

Frequently asked questions

Common questions about CAPEC-102.

What is CAPEC-102?

Session sidejacking takes advantage of an unencrypted communication channel between a victim and target system. The attacker sniffs traffic on a network looking for session tokens in unencrypted traffic. Once a session token is captured, the attacker performs malicious actions by using the stolen token with the targeted application to impersonate the victim. This attack is a specific method of session hijacking, which is exploiting a valid session token to gain unauthorized access to a target system or information. Other methods to perform a session hijacking are session fixation, cross-site scripting, or compromising a user or server machine and stealing the session token.

How does a Session Sidejacking attack work?

It typically unfolds over 4 phases. It begins with: [Detect Unprotected Session Token Transfer] The attacker sniffs on the wireless network to detect unencrypted traffic that contains session tokens.

How do you prevent CAPEC-102?

Make sure that HTTPS is used to communicate with the target system. Alternatively, use VPN if possible. It is important to ensure that all communication between the client and the server happens via an encrypted secure channel.

What weaknesses does CAPEC-102 target?

CAPEC-102 exploits 5 CWE weaknesses, including CWE-294 (Authentication Bypass by Capture-replay), CWE-319 (Cleartext Transmission of Sensitive Information), CWE-522 (Insufficiently Protected Credentials), CWE-523 (Unprotected Transport of Credentials).

How severe is CAPEC-102?

MITRE rates CAPEC-102 as High severity with high likelihood of attack.

References

Attack-pattern data is sourced from the MITRE CAPEC catalog (v3.9). Weakness associations link to the corresponding CWE entries on RadicalNotion.AI.

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Overview

Overview

How the attack works

What the attacker needs

Prerequisites

Skills required

Resources required

Consequences

How to mitigate it

Examples

Related weaknesses

Related attack patterns

Parent

Frequently asked questions

What is CAPEC-102?

How does a Session Sidejacking attack work?

How do you prevent CAPEC-102?

What weaknesses does CAPEC-102 target?

How severe is CAPEC-102?

References

Defend against CAPEC-102