Flaw found in VPN crypto security

A flaw in a popular VPN technology could allow hackers to obtain a text version of encrypted communications with only "moderate effort," a tech security body has warned.

Britain's national emergency response team, the National Infrastructure Security Coordination Centre, issued a warning this week about the safety of virtual private networks that use IPsec encryption and tunneling to connect remote workers to corporate networks.

The flaw, which the NISCC rates as "high" risk, makes it possible for an attacker to intercept IP packets traveling between two IPsec devices. They could then modify the encapsulation security payload--a subprotocol that encrypts the data being transported. This could ultimately expose this data to an unauthorized third party.

On its Web site, NISCC stated: "By making careful modifications to selected portions of the payload of the outer packet, an attacker can effect controlled changes to the header of the inner (encrypted) packet?If these messages can be intercepted by an attacker, then plaintext data is revealed."

The NISCC includes a number of solutions to this issue in its advisory.

Dan Ilett of ZDNet UK reported from London.

[Marcus Westrup]

Need a little more

Not much detail in this report - it implies that All IPsec is at risk despite the numerous implementations and protocols available. I find it hard to believe that this flaw affects all vendors.
So where is the real story?.

I Agree

Where's the beef?

This sounds like a potentially far-reaching issue. More details would be appreciated.

The real story isn't as sensational

If you read the NISCC advisory, you'll see this only applies to ESP packets that don't have an accompanying integrity check such as MD5 or SHA-1. I haven't seen any IPsec device that doesn't make use of integrity checks, but there are probably poorly designed implementations out there that make this mistake.

I would say that if you see MD5 or SHA-1 in your IPsec policy then you have nothing to worry about.

[Marcus Westrup]

Need a little more

Not much detail in this report - it implies that All IPsec is at risk despite the numerous implementations and protocols available. I find it hard to believe that this flaw affects all vendors.
So where is the real story?.

I Agree

Where's the beef?

This sounds like a potentially far-reaching issue. More details would be appreciated.

The real story isn't as sensational

If you read the NISCC advisory, you'll see this only applies to ESP packets that don't have an accompanying integrity check such as MD5 or SHA-1. I haven't seen any IPsec device that doesn't make use of integrity checks, but there are probably poorly designed implementations out there that make this mistake.

I would say that if you see MD5 or SHA-1 in your IPsec policy then you have nothing to worry about.

no story

there is no story.
The substance of the warning is: "If you misconfigure your VPN, it might not work"

the real story is that CERT and NISCC have so little of relevance to do with themselves, that they are issuing garbage like this.

Probably what happened is that someone important (therefore too important to actually read the documentation) made a stupid mistake, put his entire organization at risk, and is now forcing CERT to issue a warning. There are perhaps three people like that: someone at Homeland insecurity, someone at MI5, or someone at CERT.

no story

there is no story.
The substance of the warning is: "If you misconfigure your VPN, it might not work"

the real story is that CERT and NISCC have so little of relevance to do with themselves, that they are issuing garbage like this.

Probably what happened is that someone important (therefore too important to actually read the documentation) made a stupid mistake, put his entire organization at risk, and is now forcing CERT to issue a warning. There are perhaps three people like that: someone at Homeland insecurity, someone at MI5, or someone at CERT.