Twenty of Australia's ASX top 200 organisations have been exposed to the dangerous 'heart bleed' vulnerability in OpenSSL, which was revealed yesterday.
, an open-source implementation of the SSL
protocols, contains a bug in its heartbeat extension that validates site connections.
Attackers could exploit the read-overrun bug to quietly connect to vulnerable servers which would leak memory that could include usernames and passwords and even the SSL server's private key.
Those with access to the key could use it to impersonate a site even after the bug has been fixed, and likely crawl over and decrypt encrypted data. Man in the middle attacks could be performed by those with private keys in hand.
Scores of insecure sites have been detected and some of the biggest websites including Amazon and Wordpress have rushed to apply a patch for the two-year old vulnerability.
Yahoo! has also plugged the hole but failed to act on early advice from Google and Codenomicon researchers who tipped off some sites ahead of the disclosure yesterday. That led to the exposure of usernames and passwords
for users of its email service.
Yahoo passwords exposed
Statistics from metrics company Netcraft show that 66 percent of websites run open source web servers Apache and nginx which use OpenSSL as the default encryption system.
HackLabs director Chris Gatford ran
quick tests of the ASX top 200 organisations and found 20 which were still exposed.
He said applying the fix
would be painful for some organisations but necessary and said attackers may target the bug for a long time.
Scores more sites have been found by researchers and attackers by using simple scripts and online tools
But Google researcher Neel Mehta who helped discover the bug said exposure of private keys was unlikely due to memory allocation patterns.
While it remained critical that organisations apply the OpenSSL patch, doing so mitigated only one part of the threat.
Web administrators concerned that their website was exploited in the two years the bug existed under the radar should
obtain new digital certificates.
Those admins worried that attackers have gained access to private keys should join the few to deploy Perfect Forward Secrecy, a powerful tool to prevent attackers from decrypting data sent during the past two years.
Security boffins also advise that passwords should be changed, a step that some websites are already taking.
Organisations running the Snort security software should review a list
of signatures for the platform which will detect successful attacks against heart bleed.