Authorities have confirmed that Moalimuu is in stable condition, having received treatment for multiple injuries at a hospital in Mogadishu.
Somali media have reported the attack as the result of political tension following electoral disputes.
Moalimuu is attached to Somali Prime Minister Mohamed Hussein Roble, who recently differed with the nation's outgoing President Mohamed Abdullahi Farmaajo.
This is the second attack in a week where Al Shabaab have claimed responsibility.
Last week, the militia group attacked the norther part of Aden Adde International Airport leaving eight dead.
Somalia's fragile political situation
The Al-Qaida-affiliated Al-Shabaab terror group ruled Mogadishu until 2011 when African Union troops expelled them from the city.
They have remained in control of territory in the surrounding countryside ever since, from where they have launched frequent attacks against government and civilian targets.
Somalia has been in a state of ongoing conflict since the fall of dictator Mohammed Siad Barre in 1991. His departure left the country without a functioning government, leading to a power vacuum that was filled by warlords and militias such as Al-Shabaab.
There was a similar attack after the African Union Mission Forces signed an agreement with the Somalia National Army for joint operations. The AMISOM troops have been working to restore order in Somalia.