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1.20 deraadt 5: <title>OpenBSD Security</title>
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1.106 deraadt 18: <p>
1.294 david 19: <h2><font color="#e00000">Security</font></h2>
20: <hr>
1.1 deraadt 21:
1.406 deraadt 22: For security advisories for specific releases, click below:
1.294 david 23: <p>
1.406 deraadt 24:
1.418 tedu 25: <a href="errata21.html">2.1</a>,
26: <a href="errata22.html">2.2</a>,
27: <a href="errata23.html">2.3</a>,
28: <a href="errata24.html">2.4</a>,
29: <a href="errata25.html">2.5</a>,
30: <a href="errata26.html">2.6</a>,
31: <a href="errata27.html">2.7</a>,
32: <a href="errata28.html">2.8</a>,
33: <a href="errata29.html">2.9</a>,
34: <a href="errata30.html">3.0</a>,
35: <a href="errata31.html">3.1</a>,
36: <a href="errata32.html">3.2</a>,
37: <a href="errata33.html">3.3</a>,
38: <a href="errata34.html">3.4</a>,
39: <a href="errata35.html">3.5</a>,
40: <a href="errata36.html">3.6</a>,
1.420 schwarze 41: <a href="errata37.html">3.7</a>,
1.365 deraadt 42: <br>
1.418 tedu 43: <a href="errata38.html">3.8</a>,
44: <a href="errata39.html">3.9</a>,
45: <a href="errata40.html">4.0</a>,
46: <a href="errata41.html">4.1</a>,
47: <a href="errata42.html">4.2</a>,
48: <a href="errata43.html">4.3</a>,
49: <a href="errata44.html">4.4</a>,
50: <a href="errata45.html">4.5</a>,
51: <a href="errata46.html">4.6</a>,
52: <a href="errata47.html">4.7</a>,
53: <a href="errata48.html">4.8</a>,
54: <a href="errata49.html">4.9</a>,
55: <a href="errata50.html">5.0</a>,
56: <a href="errata51.html">5.1</a>,
57: <a href="errata52.html">5.2</a>,
58: <a href="errata53.html">5.3</a>,
1.420 schwarze 59: <a href="errata54.html">5.4</a>,
1.406 deraadt 60: <br>
1.419 jsg 61: <a href="errata55.html">5.5</a>,
1.420 schwarze 62: <a href="errata56.html">5.6</a>,
63: <a href="errata57.html">5.7</a>.
1.406 deraadt 64: <br>
1.56 deraadt 65: <hr>
66:
1.294 david 67: <a name="goals"></a>
1.278 deraadt 68: <ul>
1.406 deraadt 69: <li><h3><font color="#e00000">Goals</font></h3><p>
1.22 deraadt 70:
1.14 deraadt 71: OpenBSD believes in strong security. Our aspiration is to be NUMBER
1.22 deraadt 72: ONE in the industry for security (if we are not already there). Our
73: open software development model permits us to take a more
74: uncompromising view towards increased security than Sun, SGI, IBM, HP,
75: or other vendors are able to. We can make changes the vendors would
1.27 deraadt 76: not make. Also, since OpenBSD is exported with <a href=crypto.html>
1.45 deraadt 77: cryptography</a>, we are able to take cryptographic approaches towards
78: fixing security problems.<p>
1.18 deraadt 79:
1.288 matthieu 80: <a name="disclosure"></a>
1.294 david 81: <li><h3><font color="#e00000">Full Disclosure</font></h3><p>
1.106 deraadt 82:
1.45 deraadt 83: Like many readers of the
1.196 jufi 84: <a href="http://online.securityfocus.com/archive/1">
1.18 deraadt 85: BUGTRAQ mailing list</a>,
1.106 deraadt 86: we believe in full disclosure of security problems. In the
87: operating system arena, we were probably the first to embrace
88: the concept. Many vendors, even of free software, still try
89: to hide issues from their users.<p>
90:
91: Security information moves very fast in cracker circles. On the other
92: hand, our experience is that coding and releasing of proper security
93: fixes typically requires about an hour of work -- very fast fix
94: turnaround is possible. Thus we think that full disclosure helps the
95: people who really care about security.<p>
96:
1.288 matthieu 97: <a name="process"></a>
1.294 david 98: <li><h3><font color="#e00000">Audit Process</font></h3><p>
1.15 deraadt 99:
1.12 deraadt 100: Our security auditing team typically has between six and twelve
1.45 deraadt 101: members who continue to search for and fix new security holes. We
102: have been auditing since the summer of 1996. The process we follow to
103: increase security is simply a comprehensive file-by-file analysis of
1.106 deraadt 104: every critical software component. We are not so much looking for
105: security holes, as we are looking for basic software bugs, and if
1.138 deraadt 106: years later someone discovers the problem used to be a security
1.106 deraadt 107: issue, and we fixed it because it was just a bug, well, all the
108: better. Flaws have been found in just about every area of the system.
109: Entire new classes of security problems have been found during our
110: audit, and often source code which had been audited earlier needs
111: re-auditing with these new flaws in mind. Code often gets audited
112: multiple times, and by multiple people with different auditing
113: skills.<p>
1.12 deraadt 114:
1.94 deraadt 115: Some members of our security auditing team worked for Secure Networks,
116: the company that made the industry's premier network security scanning
117: software package Ballista (Secure Networks got purchased by Network
118: Associates, Ballista got renamed to Cybercop Scanner, and well...)
119: That company did a lot of security research, and thus fit in well
1.106 deraadt 120: with the OpenBSD stance. OpenBSD passed Ballista's tests with flying
121: colours since day 1.<p>
1.31 deraadt 122:
1.34 deraadt 123: Another facet of our security auditing process is its proactiveness.
1.45 deraadt 124: In most cases we have found that the determination of exploitability
125: is not an issue. During our ongoing auditing process we find many
126: bugs, and endeavor to fix them even though exploitability is not
127: proven. We fix the bug, and we move on to find other bugs to fix. We
128: have fixed many simple and obvious careless programming errors in code
129: and only months later discovered that the problems were in fact
130: exploitable. (Or, more likely someone on
1.197 jufi 131: <a href="http://online.securityfocus.com/archive/1">BUGTRAQ</a>
1.45 deraadt 132: would report that other operating systems were vulnerable to a `newly
133: discovered problem', and then it would be discovered that OpenBSD had
134: been fixed in a previous release). In other cases we have been saved
135: from full exploitability of complex step-by-step attacks because we
136: had fixed one of the intermediate steps. An example of where we
1.94 deraadt 137: managed such a success is the lpd advisory that Secure Networks put out.
138: <p>
1.29 deraadt 139:
1.288 matthieu 140: <a name="newtech"></a>
1.294 david 141: <li><h3><font color="#e00000">New Technologies</font></h3><p>
1.278 deraadt 142:
143: As we audit source code, we often invent new ways of solving problems.
144: Sometimes these ideas have been used before in some random application
145: written somewhere, but perhaps not taken to the degree that we do.
146: <p>
147:
148: <ul>
149: <li>strlcpy() and strlcat()
150: <li>Memory protection purify
151: <ul>
152: <li>W^X
153: <li>.rodata segment
154: <li>Guard pages
155: <li>Randomized malloc()
156: <li>Randomized mmap()
157: <li>atexit() and stdio protection
158: </ul>
1.295 otto 159: <li>Privilege separation
1.278 deraadt 160: <li>Privilege revocation
161: <li>Chroot jailing
162: <li>New uids
163: <li>ProPolice
164: <li>... and others
165: </ul>
166: <p>
167:
1.294 david 168: <li><h3><font color="#e00000">The Reward</font></h3><p>
1.106 deraadt 169:
1.45 deraadt 170: Our proactive auditing process has really paid off. Statements like
1.35 deraadt 171: ``This problem was fixed in OpenBSD about 6 months ago'' have become
1.45 deraadt 172: commonplace in security forums like
1.197 jufi 173: <a href="http://online.securityfocus.com/archive/1">BUGTRAQ</a>.<p>
1.35 deraadt 174:
1.45 deraadt 175: The most intense part of our security auditing happened immediately
1.80 espie 176: before the OpenBSD 2.0 release and during the 2.0->2.1 transition,
1.45 deraadt 177: over the last third of 1996 and first half of 1997. Thousands (yes,
178: thousands) of security issues were fixed rapidly over this year-long
179: period; bugs like the standard buffer overflows, protocol
180: implementation weaknesses, information gathering, and filesystem
181: races. Hence most of the security problems that we encountered were
182: fixed before our 2.1 release, and then a far smaller number needed
183: fixing for our 2.2 release. We do not find as many problems anymore,
184: it is simply a case of diminishing returns. Recently the security
185: problems we find and fix tend to be significantly more obscure or
186: complicated. Still we will persist for a number of reasons:<p>
1.36 deraadt 187:
1.35 deraadt 188: <ul>
1.45 deraadt 189: <li>Occasionally we find a simple problem we missed earlier. Doh!
1.35 deraadt 190: <li>Security is like an arms race; the best attackers will continue
1.45 deraadt 191: to search for more complicated exploits, so we will too.
192: <li>Finding and fixing subtle flaws in complicated software is
193: a lot of fun.
1.35 deraadt 194: </ul>
1.106 deraadt 195: <p>
1.15 deraadt 196:
1.14 deraadt 197: The auditing process is not over yet, and as you can see we continue
1.28 deraadt 198: to find and fix new security flaws.<p>
1.12 deraadt 199:
1.288 matthieu 200: <a name="default"></a>
1.294 david 201: <li><h3><font color="#e00000">"Secure by Default"</font></h3><p>
1.106 deraadt 202:
203: To ensure that novice users of OpenBSD do not need to become security
204: experts overnight (a viewpoint which other vendors seem to have), we
205: ship the operating system in a Secure by Default mode. All non-essential
206: services are disabled. As the user/administrator becomes more familiar
207: with the system, he will discover that he has to enable daemons and other
208: parts of the system. During the process of learning how to enable a new
209: service, the novice is more likely to learn of security considerations.<p>
210:
211: This is in stark contrast to the increasing number of systems that
212: ship with NFS, mountd, web servers, and various other services enabled
213: by default, creating instantaneous security problems for their users
214: within minutes after their first install.<p>
215:
1.288 matthieu 216: <a name="crypto"></a>
1.294 david 217: <li><h3><font color="#e00000">Cryptography</font></h3><p>
1.106 deraadt 218:
219: And of course, since the OpenBSD project is based in Canada, it is possible
220: for us to integrate cryptography. For more information, read the page
1.116 deraadt 221: outlining <a href=crypto.html>what we have done with cryptography</a>.</p>
1.106 deraadt 222:
1.294 david 223: <li><h3><font color="#e00000">Advisories</font></h3><p>
1.106 deraadt 224:
1.418 tedu 225: Please refer to the links at the top of this page.
1.106 deraadt 226:
1.288 matthieu 227: <a name="watching"></a>
1.294 david 228: <li><h3><font color="#e00000">Watching our Changes</font></h3><p>
1.106 deraadt 229:
1.21 deraadt 230: Since we take a proactive stance with security, we are continually
231: finding and fixing new security problems. Not all of these problems
1.80 espie 232: get widely reported because (as stated earlier) many of them are not
1.45 deraadt 233: confirmed to be exploitable; many simple bugs we fix do turn out to
234: have security consequences we could not predict. We do not have the
235: time resources to make these changes available in the above format.<p>
1.21 deraadt 236:
237: Thus there are usually minor security fixes in the current source code
238: beyond the previous major OpenBSD release. We make a limited
1.45 deraadt 239: guarantee that these problems are of minimal impact and unproven
1.44 ian 240: exploitability. If we discover that a problem definitely matters for
1.45 deraadt 241: security, patches will show up here <strong>VERY</strong> quickly.<p>
1.21 deraadt 242:
1.45 deraadt 243: People who are really concerned with security can do a number of
244: things:<p>
1.21 deraadt 245:
246: <ul>
247: <li>If you understand security issues, watch our
1.294 david 248: <a href="mail.html">source-changes mailing list</a> and keep an
1.23 deraadt 249: eye out for things which appear security related. Since
1.21 deraadt 250: exploitability is not proven for many of the fixes we make,
251: do not expect the relevant commit message to say "SECURITY FIX!".
252: If a problem is proven and serious, a patch will be available
253: here very shortly after.
1.161 horacio 254: <li>In addition to source changes, you can watch our <a href="mail.html">
1.160 ericj 255: security-announce mailing list</a> which will notify you for every
1.186 ian 256: security related item that the OpenBSD team deems as a possible threat,
1.160 ericj 257: and instruct you on how to patch the problem.
1.21 deraadt 258: <li>Track our current source code tree, and teach yourself how to do a
1.29 deraadt 259: complete system build from time to time (read /usr/src/Makefile
260: carefully). Users can make the assumption that the current
261: source tree always has stronger security than the previous release.
1.45 deraadt 262: However, building your own system from source code is not trivial;
1.397 deraadt 263: it is nearly 850MB of source code, and problems do occur as we
1.45 deraadt 264: transition between major releases.
1.115 ericj 265: <li>Install a binary snapshot for your
1.80 espie 266: architecture, which are made available fairly often. For
1.413 matthieu 267: instance, an i386 snapshot is typically made available weekly.
1.21 deraadt 268: </ul>
269:
1.9 deraadt 270: <p>
1.288 matthieu 271: <a name="reporting"></a>
1.294 david 272: <li><h3><font color="#e00000">Reporting problems</font></h3><p>
1.3 deraadt 273:
1.5 deraadt 274: <p> If you find a new security problem, you can mail it to
1.294 david 275: <a href="mailto:deraadt@openbsd.org">deraadt@openbsd.org</a>.
1.7 deraadt 276: <br>
1.5 deraadt 277: If you wish to PGP encode it (but please only do so if privacy is very
1.112 philen 278: urgent, since it is inconvenient) use this <a href="advisories/pgpkey.txt">pgp key</a>.
1.5 deraadt 279:
1.107 deraadt 280: <p>
1.288 matthieu 281: <a name="papers"></a>
1.294 david 282: <li><h3><font color="#e00000">Further Reading</font></h3><p>
1.107 deraadt 283:
1.389 lum 284: Numerous
1.404 deraadt 285: <a href="papers/index.html">papers</a> have been written by OpenBSD team members,
1.389 lum 286: many dedicated to security.
1.294 david 287: </ul>
1.1 deraadt 288:
1.24 deraadt 289: </body>
290: </html>
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