The U.S. Office of Foreign Asset Control (OFAC) manages about a dozen different sanctions systems, each with their own set of rules, and new sanctions don't necessarily have the same rules as old ones.
The legal basis of the various sanctions implicating Syria can be found here. They arise under six statutes, eight executive orders, Part 542 of Title 31 of the Code of Federal Regulations, and at least four pending regulations, as well as some UN materials that aren't directly applicable until codified in U.S. laws and regulations. There is a summary here.
The core provisions are as follows:
Current Syria sanctions (1) block the property and interests in
property of the Government of Syria pursuant to E.O. 13582, (2) block
the property and interests in property of persons listed in an Annex
to, or that are determined by the Secretary of the Treasury in
consultation with the Secretary of State, to meet the criteria
described in, E.O. 13338, E.O. 13399, E.O. 13460, E.O. 13572, E.O.
13573, E.O. 13582, or E.O. 13606, (3) prohibit transactions or
dealings with foreign persons that are determined by the Secretary of
the Treasury, in consultation with the Secretary of State, to meet the
criteria described in E.O. 13608, and (4) prohibit certain
transactions with respect to Syria pursuant to E.O. 13582.
Under E.O. 13582, all property and interests in property of the
Government of Syria, which includes its agencies, instrumentalities,
and controlled entities, which are in the United States or within the
possession or control of U.S. persons, are blocked.
E.O. 13582 also prohibits the following:
• New investment in Syria by a U.S. person, wherever located;
• The direct or indirect exportation, reexportation, sale, or supply
of any services to Syria from the United States or by a U.S. person,
wherever located;
• The importation into the United States of petroleum or petroleum
products of Syrian origin;
• Any transaction or dealing by a U.S. person, wherever located, in or
related to petroleum or petroleum products of Syrian origin; and
• Any approval, financing, facilitation, or guarantee by a U.S.
person, wherever located, of a transaction by a foreign person where
the transaction by that foreign person would be prohibited if
performed by a U.S. person or within the United States.
The names of persons listed in an Annex or designated pursuant to E.O.
13338, E.O. 13399, E.O. 13460, E.O. 13572, E.O. 13573, or E.O. 13582,
whose property and interests in property are therefore blocked, are
published in the Federal Register and incorporated into OFAC’s
Specially Designated Nationals and Blocked Persons List (“SDN List”)
with the identifier “[SYRIA].” The names of persons listed in an Annex
or designated pursuant to E.O. 13606, whose property and interests in
property are therefore blocked, are published in the Federal Register
and incorporated into OFAC’s SDN List with the identifier “[HRIT-SY].”
The names of foreign persons identified pursuant to E.O. 13608 are
published in the Federal Register and incorporated into OFAC’s SDN
List with the identifier “[FSE-SY],” The SDN List is available through
the following page on OFAC’s Web site: www.treasury.gov/sdn.
Most, but not all, of the sanctions with Syria involve specific named individuals wherever they may be in the world.
Also, in general, sanctions are imposed based upon nationality and not based upon residency. The question seems to assume that address on file with the bank is the controlling factor, but this is unlikely.
Furthermore, there is a special set of rules that exist specifically to prevent people from circumventing sanctions and you need to be wary of violating those as well when otherwise you might not be subject to the sanctions at all.
The rules are highly technical and not easily summarized in a Law.SE answer.
