Talos Rules 2021-08-06
This release adds and modifies rules in several categories.

Talos is releasing new and updated coverage for a Microsoft Exchange vulnerability patched in July 2021, CVE-2021-34473. This vulnerability is a pre-authentication ACL bypass vulnerability, and the updates provided in this latest SRU offer additional protection against exploitation based on new information shared at and after Black Hat USA 2021. The covering SIDs are: 57906-57909 and 57983.

Talos has added and modified multiple rules in the server-webapp rule sets to provide coverage for emerging threats from these technologies.

Change logs

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091800.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091701.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091700.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091601.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091600.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091501.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091401.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091300.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2091101.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3000.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (snort3-server-webapp.rules)

Modified Rules:


 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (snort3-server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (snort3-server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (snort3-server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (snort3-server-webapp.rules)

2021-08-06 18:19:27 UTC

Snort Subscriber Rules Update

Date: 2021-08-06

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 2983.

The format of the file is:

gid:sid <-> Default rule state <-> Message (rule group)

New Rules:


 * 1:57983 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

Modified Rules:


 * 1:57907 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57906 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57908 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)
 * 1:57909 <-> ENABLED <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt (server-webapp.rules)

2021-08-06 18:20:57 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.0.3.1.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:57 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.0.3.4.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:57 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.0.0.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:58 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.0.1.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:58 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.1.0.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:58 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.3.0.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:58 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.4.0.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:58 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.5.0.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:58 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.7.0.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt


2021-08-06 18:20:58 UTC

Snort Subscriber Rules Update

Date: 2021-08-06-001

This is the complete list of rules modified and added in the Sourcefire VRT Certified rule pack for Snort version 3.1.9.0.

The format of the file is:

gid:sid <-> Message

New Rules:

* 1:57983 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt

Modified Rules:

* 1:57906 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57907 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57908 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt
* 1:57909 <-> SERVER-WEBAPP Microsoft Exchange autodiscover server side request forgery attempt