Rule Category

SERVER-OTHER -- Snort has detected traffic exploiting vulnerabilities in a server in the network.

Alert Message

SERVER-OTHER Apache Log4j logging remote code execution attempt

Rule Explanation

This rule looks for attempts to exploit a remote code execution vulnerability in Log4j's "Lookup" functionality.

What To Look For

This rule looks for attempts to exploit a remote code execution vulnerability in Log4j's "Lookup" functionality.

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

Rule Groups

No rule groups

CVE

Rule Vulnerability

Remote File Inclusion

Remote File Inclusion (RFI) attacks occur when a webserver takes a file crafted by an attacker as input and runs or stores it in an unsafe manner. For instance, the webserver could accept an image file that is actually code, then call it to execute after uploading. RFI attacks happen on web applications that dynamically include external files or scripts. A successful RFI can lead to data leaks, remote code execution, or cross site scripting. Avoid dynamic inclusion of user input files, or whitelist files that may be included. Keep the PHP allow_url_include option set to off; this will not protect against Local File Inclusion attacks.

CVE Additional Information

This product uses data from the NVD API but is not endorsed or certified by the NVD.
CVE-2021-44228
Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.
Details
Severity Base Score10
Impact Score6 Exploit Score3.9
Confidentiality ImpactHIGH Integrity ImpactHIGH
Availability ImpactHIGHAttack VectorNETWORK
ScopeCHANGEDUser InteractionNONE
Authentication Ease of AccessLOW
Privileges RequiredNONE
CVE-2021-45046
It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.
Details
Severity Base Score9
Impact Score6 Exploit Score2.2
Confidentiality ImpactHIGH Integrity ImpactHIGH
Availability ImpactHIGHAttack VectorNETWORK
ScopeCHANGEDUser InteractionNONE
Authentication Ease of AccessHIGH
Privileges RequiredNONE
CVE-2021-45105
Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.
Details
Severity Base Score5.9
Impact Score3.6 Exploit Score2.2
Confidentiality ImpactNONE Integrity ImpactNONE
Availability ImpactHIGHAttack VectorNETWORK
ScopeUNCHANGEDUser InteractionNONE
Authentication Ease of AccessHIGH
Privileges RequiredNONE

MITRE ATT&CK Framework

Tactic: Initial Access

Technique: Exploit Public-Facing Application

For reference, see the MITRE ATT&CK vulnerability types here: https://attack.mitre.org