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Remote Command Injection in Ruby Gem sfpagent 0.4.14


From: "Larry W. Cashdollar" <larry0 () me com>
Date: Tue, 15 Apr 2014 20:02:54 -0400

Title: Remote Command Injection in Ruby Gem sfpagent 0.4.14

Date: 4/15/2014

Author: Larry W. Cashdollar, @_larry0

CVE: Please assign one at your leisure. 

Download: http://rubygems.org/gems/sfpagent

Vulnerability
The list variable generated from the user supplied JSON[body] input is passed directly to the system() shell on line 
649. If a user supplies a module name with shell metacharacters like ; they might be able to execute shell commands on 
the remote system as the sfpagent running user id.
I think to fix this youâ€TMd need to sanitize all input from the user with shellwords.escape.

637                         code, body = get_data(address, port, '/modules')
638                         raise Exception, "Unable to get modules list from {name}" if code.to_i != 200
639 
640                         modules = JSON[body]
641                         list = ''
642                         schemata.each { |m|
643                                 list += "{m} " if File.exist?("{modules_dir}/{m}") and
644                                                    (not modules.has_key?(m) or modules[m] != 
get_local_module_hash(m, modules_dir).to_s)
645                         }
646 
647                         return true if list == ''
648 
649                         if system("cd #{modules_dir}; #{install_module} #{address} #{port} #{list} 1>/dev/null 
2>/tmp/install_module.error")
650                                 Sfp::Agent.logger.info "Push modules #{list}to #{name} [OK]"
651                         else
652                                 Sfp::Agent.logger.warn "Push modules #{list}to #{name} [Failed]"
653                         end
654 
655                         return true

Vendor: Notified 4/15/14. Version 0.4.15 fixes this issue.

Advisory: http://www.vapid.dhs.org/advisories/spfagent-remotecmd.html

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