apt-get update hangs or exits with error after terminating with double Ctrl+C

[Yuri]

It is easier to reproduce bug on systems with poor performance, like VM.
Reproduced situation on trusty, lucid, precise.

I'm doing sudo apt-get update, then after the first source and before last source will be downloaded, i've pressed Ctrl+C double times very fast. After this, i have three scenarios of unpredictable behavior.

1) Hangs on "100% [Waiting for headers] " forever
2) Lot of "Err http://some_source.dst release
                    Bad header line [IP: some_ip 80]" messages.
3) Exits with message "Some index files failed to download. They have been ignored, or old ones used instead."

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: apt 1.0.1ubuntu2.6
ProcVersionSignature: Ubuntu 3.13.0-40.69-generic 3.13.11.10
Uname: Linux 3.13.0-40-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
Date: Wed Dec 17 18:03:19 2014
InstallationDate: Installed on 2014-10-07 (71 days ago)
InstallationMedia: Ubuntu-Server 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.3)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=ru_RU.UTF-8
 SHELL=/bin/bash
SourcePackage: apt
UpgradeStatus: No upgrade log present (probably fresh install)