“Haf­ni­um” vul­nerabi­li­ties in Micro­soft Exch­an­ge: duty of noti­fi­ca­ti­on and com­mu­ni­ca­ti­on in accordance with the GDPR?

The “Haf­ni­um” Secu­ri­ty Vulnerabilities

“Haf­ni­um” is the umbrel­la term for mul­ti­ple secu­ri­ty vul­nerabi­li­ties in Micro­soft Exch­an­ge ser­vers. Ger­many’s Fede­ral Office for Infor­ma­ti­on Secu­ri­ty (BSI) has been empha­ti­cal­ly war­ning about the­se thre­ats (only in Ger­man) sin­ce last week, as com­pa­nies using unpatched Micro­soft Exch­an­ge ser­vers in a cer­tain con­fi­gu­ra­ti­on may be vul­nerable to attacks from the inter­net. The name “Haf­ni­um” refers to a group of Chi­ne­se hackers which is cre­di­ted with the attacks. Accor­ding to Micro­soft and BSI, the fol­lo­wing Exch­an­ge ser­ver ver­si­ons are affec­ted if they are self-hosting, i.e. ope­ra­ted as on-premises sys­tems, and acces­si­ble via the inter­net with untrust­wor­t­hy con­nec­tions to Port 443:

  • Exch­an­ge Ser­ver 2010 (RU 31 for Ser­vice Pack 3)
  • Exch­an­ge Ser­ver 2013 (CU 23)
  • Exch­an­ge Ser­ver 2016 (CU 19, CU 18)
  • Exch­an­ge Ser­ver 2019 (CU 8, CU 7)

More infor­ma­ti­on about the­se thre­ats and the mea­su­res which need to be taken can be found in the detail­ed infor­ma­ti­on pro­vi­ded by BSI (only in Ger­man) and in the gui­dance from HiSo­lu­ti­ons AG. The vul­nerabi­li­ties are alre­a­dy being exploi­ted, poten­ti­al­ly giving atta­ckers access to all the data on the ser­ver, inclu­ding e‑mail mail­bo­xes and address books. The vul­nerabi­li­ties can also be used to launch fur­ther attacks on com­pa­nies, a thre­at which can­not be con­clu­si­ve­ly asses­sed at this time.

Over­view: what the aut­ho­ri­ties are saying

What makes the pre­sent case uni­que is that it invol­ves an espe­ci­al­ly cri­ti­cal vul­nerabi­li­ty which is alre­a­dy being actively exploi­ted. As can be seen from the over­view below (down­load PDF here), some super­vi­so­ry aut­ho­ri­ties, inclu­ding the Bava­ri­an Data Pro­tec­tion Aut­ho­ri­ty and the Data Pro­tec­tion Com­mis­sio­ner of Lower Sax­o­ny (only in Ger­man), take the view that noti­fi­ca­ti­on is requi­red even if the sys­tem was not actual­ly com­pro­mi­sed, if updates were not instal­led on time.

Assess­ment in Data Pro­tec­tion Law

The idea that cyber­at­tacks and IT secu­ri­ty inci­dents and mea­su­res to hand­le such inci­dents could have legal con­se­quen­ces requi­ring a legal inci­dent respon­se is not­hing new. Howe­ver, the mere need to install a secu­ri­ty update does not trig­ger a duty of noti­fi­ca­ti­on or com­mu­ni­ca­ti­on in accordance with Artic­le 33 or 34 of the GDPR (only in Ger­man); at most, the con­trol­ler would be requi­red to docu­ment the inci­dent in accordance with Artic­le 33(5) of the GDPR (only in Ger­man). This docu­men­ta­ti­on should be detail­ed enough to demons­tra­te that no data breach occur­red or, in any case, that the inci­dent did not crea­te a risk to the rights and free­doms of natu­ral per­sons. Along with docu­men­ting the inci­dent, con­trol­lers should also secu­re all rele­vant evi­dence which may be useful to sup­port the docu­men­ta­ti­on or for other aspects of the legal hand­ling of the inci­dent (e.g. to enforce or defend against regres­si­on claims). If a risk can­not be ruled out, the com­pe­tent data pro­tec­tion aut­ho­ri­ty must be noti­fied in accordance with Artic­le 33(1) of the GDPR (only in Ger­man). In urgent cases, this noti­fi­ca­ti­on must be made wit­hout undue delay, if pos­si­ble within 72 hours of when the con­trol­ler beco­mes awa­re of the data breach. If the noti­fi­ca­ti­on is late, the con­trol­ler is requi­red to cite reasons for the delay. If the­re is a high risk as a result of the data breach, the data sub­jects must also be noti­fied in accordance with Artic­le 34(1) of the GDPR (only in Ger­man).

Based on the­se prin­ci­ples, the super­vi­so­ry aut­ho­ri­ties are cor­rect in sta­ting that con­trol­lers are gene­ral­ly requi­red to noti­fy them if they find that the Exch­an­ge ser­ver has been com­pro­mi­sed. Howe­ver, it is not the case that mere­ly being late to install updates would estab­lish a duty of noti­fi­ca­ti­on, as it is not evi­dent in this case why this would crea­te a legal­ly rele­vant risk. In cases whe­re a sys­tem is demons­tra­b­ly com­pro­mi­sed but no data leak has been dis­co­ver­ed, a detail­ed indi­vi­du­al check should be per­for­med in order to cla­ri­fy the ext­ent to which the sys­tem was affec­ted by the attack. Depen­ding on the results of this check, a decis­i­on can then be made as to whe­ther noti­fi­ca­ti­on is requi­red based on the abo­ve prin­ci­ples. In case of doubt, or in situa­tions which do not allow for com­ple­te inves­ti­ga­ti­on or docu­men­ta­ti­on, we would tend to recom­mend noti­fy­ing the aut­ho­ri­ty. On the other hand, noti­fi­ca­ti­on of data sub­jects would only come into con­side­ra­ti­on in cases of high risk. This may be the case, for exam­p­le, if the­re is a leak invol­ving sen­si­ti­ve per­so­nal data, but an assess­ment is requi­red in each indi­vi­du­al case.

Recom­men­da­ti­on

First, and most important­ly: accor­ding to BSI (only in Ger­man), about 25,000 sys­tems in Ger­ma­ny were still vul­nerable as of 11 March The Bava­ri­an Data Pro­tec­tion Aut­ho­ri­ty has also repor­ted that it has alre­a­dy iden­ti­fied vul­nerable sys­tems (PDF only in Ger­man) and cont­ac­ted their ope­ra­tors. Accor­din­gly, com­pa­nies should take urgent action to ensu­re that secu­ri­ty updates are pro­per­ly instal­led, as well as che­cking the sys­tems they use to deter­mi­ne if they are com­pro­mi­sed, if they have not done so alre­a­dy. Com­pa­nies should also check in each case whe­ther they are requi­red to noti­fy an aut­ho­ri­ty or com­mu­ni­ca­te a data breach in accordance with the GDPR or ano­ther sta­tu­te, such as the Tele­com­mu­ni­ca­ti­ons Act or the BSI Act. Regard­less of the fact that the legal views expres­sed by the aut­ho­ri­ties in Bava­ria and Lower Sax­o­ny are uncon­vin­cing, con­trol­lers who are sub­ject to regu­la­ti­on by tho­se aut­ho­ri­ties should nevert­hel­ess take into account the risk of fail­ure to com­ply and con­sider a pre­ven­ti­ve noti­fi­ca­ti­on.

The Cyber­se­cu­ri­ty & Data Pro­tec­tion team at reusch­law Legal Con­sul­tants pro­vi­des com­pre­hen­si­ve advice in all legal ques­ti­ons rela­ting to IT secu­ri­ty. Should you requi­re legal assis­tance in hand­ling the “Haf­ni­um” vul­nerabi­li­ties, we would be glad to assist you.

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