Mother-of-two Natalya, a post office worker, was collecting birch sap in a forest near Tynda in Amur region with a friend when the attack happened. A shocking picture taken by police shows her lying under the pile of foliage where the bear had buried her, a clawed and bloodied arm visible.
The Mirror has decided not to show the image because it was deemed too graphic.
Natalya had a miracle escape after her friend fled to raise the alarm with the emergency services.
She is now fighting for her life in a Russian hospital.
Although her dog barked to sound the alarm, the warning came too late and she and the pet were overwhelmed by the wild animal.
"The bear evidently thought the woman was dead and sought to bury her and hide its prey, apparently saving its next meal," reported The Siberian Times.
Rescuers arrived at the scene and shot the bear - a four-year-old female - dead when it attacked them.
Then they noticed the woman's arm jutting out of a pile of leaves and sticks, bloodied with bear claw wounds.
The woman was "alive and conscious" despite serious injuries.
Her first question was: "Have you killed the bear?"
Mrs Pasternak suffered serious scalp and thigh wounds, and was in "deep shock".
Doctors at Tynda Hospital said she remained in a 'severe' condition with her two adult children at her bedside.
Source: UK Mirror