diff --git a/src/gmp/models/filter/__tests__/convert.js b/src/gmp/models/filter/__tests__/convert.js
index 8012536885..89d941e666 100644
--- a/src/gmp/models/filter/__tests__/convert.js
+++ b/src/gmp/models/filter/__tests__/convert.js
@@ -248,6 +248,20 @@ describe('convert tests', () => {
       value: 'regexp',
     });
   });
+
+  test('should return correct value and relation when keyword is a number or number string', () => {
+    expect(convert('123', '456', '=')).toEqual({
+      value: '123=456',
+      relation: '~',
+    });
+  });
+
+  test('should return correct value and relation when keyword is a number', () => {
+    expect(convert(123, 456, ':')).toEqual({
+      value: '123:456',
+      relation: '~',
+    });
+  });
 });
 
 // vim: set ts=2 sw=2 tw=80:
diff --git a/src/gmp/models/filter/convert.js b/src/gmp/models/filter/convert.js
index c94fa8a1c1..40be6da10d 100644
--- a/src/gmp/models/filter/convert.js
+++ b/src/gmp/models/filter/convert.js
@@ -16,7 +16,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-import {isDefined} from '../../utils/identity';
+import {isDefined, isNumberOrNumberString} from '../../utils/identity';
 import {isEmpty} from '../../utils/string';
 
 import {parseInt} from '../../parser';
@@ -87,6 +87,10 @@ const convert = (keyword, value, relation) => {
     return {value, relation};
   }
 
+  if (isNumberOrNumberString(keyword)) {
+    return {value: `${keyword}${relation}${value}`, relation: '~'};
+  }
+
   return {
     value,
     keyword,
diff --git a/src/gmp/models/filter/filterterm.js b/src/gmp/models/filter/filterterm.js
index acaf5a0c57..4f06cc4b59 100644
--- a/src/gmp/models/filter/filterterm.js
+++ b/src/gmp/models/filter/filterterm.js
@@ -39,7 +39,7 @@ class FilterTerm {
    * @param {String} relation Relation between keyword and filter, =,<,>,...
    */
   constructor({keyword, value, relation}) {
-    this.keyword = isDefined(keyword) ? keyword.toLowerCase() : keyword;
+    this.keyword = isDefined(keyword) ? String(keyword).toLowerCase() : keyword;
     this.value = value;
     this.relation = relation;
   }
diff --git a/src/gmp/utils/identity.js b/src/gmp/utils/identity.js
index 8287a8eacf..6cd9b98666 100644
--- a/src/gmp/utils/identity.js
+++ b/src/gmp/utils/identity.js
@@ -15,6 +15,9 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
+
+import {parseFloat} from 'gmp/parser';
+
 export const {isArray} = global.Array;
 
 export const isDefined = value => value !== undefined;
@@ -29,6 +32,8 @@ export const isNull = value => value === null;
 
 export const isNumber = value => typeof value === 'number';
 
+export const isNumberOrNumberString = value => !isNaN(parseFloat(value));
+
 export const isFunction = value => typeof value === 'function';
 
 export const isJsDate = value =>