The incident happened in the Marshalls parking lot on Ventura Boulevard.
The woman was getting into her car at about 8:30 p.m. Thursday when she was attacked.
The suspect held a knife to her throat as he got in the back seat. That's when police say the woman began honking her horn to try and get someone's attention.
The suspect let go of the woman and ran off. The woman was not hurt. Police are still searching for the suspect.