Annotation of www/security.html, Revision 1.445
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1.430 tj 5: <title>OpenBSD: Security</title>
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1.432 tb 8: <link rel="canonical" href="https://www.openbsd.org/security.html">
1.1 deraadt 9:
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1.428 tb 15:
1.441 bentley 16: <h2 id=OpenBSD>
1.425 deraadt 17: <a href="index.html">
1.441 bentley 18: <i>Open</i><b>BSD</b></a>
19: Security
1.427 tb 20: </h2>
1.441 bentley 21:
1.294 david 22: <hr>
1.441 bentley 23:
1.429 tj 24: <p>
1.441 bentley 25: For security advisories for specific releases, click below:
1.1 deraadt 26:
1.294 david 27: <p>
1.406 deraadt 28:
1.444 schwarze 29: <a href="errata20.html">2.0</a>,
1.418 tedu 30: <a href="errata21.html">2.1</a>,
31: <a href="errata22.html">2.2</a>,
32: <a href="errata23.html">2.3</a>,
33: <a href="errata24.html">2.4</a>,
34: <a href="errata25.html">2.5</a>,
35: <a href="errata26.html">2.6</a>,
36: <a href="errata27.html">2.7</a>,
37: <a href="errata28.html">2.8</a>,
38: <a href="errata29.html">2.9</a>,
39: <a href="errata30.html">3.0</a>,
40: <a href="errata31.html">3.1</a>,
41: <a href="errata32.html">3.2</a>,
42: <a href="errata33.html">3.3</a>,
43: <a href="errata34.html">3.4</a>,
44: <a href="errata35.html">3.5</a>,
1.444 schwarze 45: <br>
1.418 tedu 46: <a href="errata36.html">3.6</a>,
1.420 schwarze 47: <a href="errata37.html">3.7</a>,
1.418 tedu 48: <a href="errata38.html">3.8</a>,
49: <a href="errata39.html">3.9</a>,
50: <a href="errata40.html">4.0</a>,
51: <a href="errata41.html">4.1</a>,
52: <a href="errata42.html">4.2</a>,
53: <a href="errata43.html">4.3</a>,
54: <a href="errata44.html">4.4</a>,
55: <a href="errata45.html">4.5</a>,
56: <a href="errata46.html">4.6</a>,
57: <a href="errata47.html">4.7</a>,
58: <a href="errata48.html">4.8</a>,
59: <a href="errata49.html">4.9</a>,
60: <a href="errata50.html">5.0</a>,
61: <a href="errata51.html">5.1</a>,
1.444 schwarze 62: <br>
1.418 tedu 63: <a href="errata52.html">5.2</a>,
64: <a href="errata53.html">5.3</a>,
1.420 schwarze 65: <a href="errata54.html">5.4</a>,
1.419 jsg 66: <a href="errata55.html">5.5</a>,
1.420 schwarze 67: <a href="errata56.html">5.6</a>,
1.423 benno 68: <a href="errata57.html">5.7</a>,
1.431 deraadt 69: <a href="errata58.html">5.8</a>,
70: <a href="errata59.html">5.9</a>,
1.434 tj 71: <a href="errata60.html">6.0</a>,
1.435 deraadt 72: <a href="errata61.html">6.1</a>,
1.436 deraadt 73: <a href="errata62.html">6.2</a>,
1.437 deraadt 74: <a href="errata63.html">6.3</a>,
1.440 deraadt 75: <a href="errata64.html">6.4</a>,
1.443 deraadt 76: <a href="errata65.html">6.5</a>,
1.445 ! deraadt 77: <a href="errata66.html">6.6</a>,
! 78: <a href="errata67.html">6.7</a>.
1.406 deraadt 79: <br>
1.56 deraadt 80: <hr>
81:
1.278 deraadt 82: <ul>
1.441 bentley 83: <li><h3 id=goals>Goals</h3>
1.22 deraadt 84:
1.441 bentley 85: <p>
1.14 deraadt 86: OpenBSD believes in strong security. Our aspiration is to be NUMBER
1.22 deraadt 87: ONE in the industry for security (if we are not already there). Our
88: open software development model permits us to take a more
1.442 deraadt 89: uncompromising view towards increased security than most vendors are
1.424 tb 90: able to. We can make changes the vendors would
1.27 deraadt 91: not make. Also, since OpenBSD is exported with <a href=crypto.html>
1.45 deraadt 92: cryptography</a>, we are able to take cryptographic approaches towards
1.441 bentley 93: fixing security problems.
1.18 deraadt 94:
1.441 bentley 95: <li><h3 id=disclosure>Full Disclosure</h3>
1.106 deraadt 96:
1.441 bentley 97: <p>
1.45 deraadt 98: Like many readers of the
1.438 tb 99: <a href="https://www.securityfocus.com/archive/1">
1.18 deraadt 100: BUGTRAQ mailing list</a>,
1.106 deraadt 101: we believe in full disclosure of security problems. In the
102: operating system arena, we were probably the first to embrace
103: the concept. Many vendors, even of free software, still try
1.441 bentley 104: to hide issues from their users.
1.106 deraadt 105:
1.441 bentley 106: <p>
1.106 deraadt 107: Security information moves very fast in cracker circles. On the other
108: hand, our experience is that coding and releasing of proper security
1.441 bentley 109: fixes typically requires about an hour of work — very fast fix
1.106 deraadt 110: turnaround is possible. Thus we think that full disclosure helps the
111: people who really care about security.<p>
112:
1.441 bentley 113: <li><h3 id=process>Audit Process</h3>
1.15 deraadt 114:
1.441 bentley 115: <p>
1.12 deraadt 116: Our security auditing team typically has between six and twelve
1.45 deraadt 117: members who continue to search for and fix new security holes. We
118: have been auditing since the summer of 1996. The process we follow to
119: increase security is simply a comprehensive file-by-file analysis of
1.106 deraadt 120: every critical software component. We are not so much looking for
121: security holes, as we are looking for basic software bugs, and if
1.138 deraadt 122: years later someone discovers the problem used to be a security
1.106 deraadt 123: issue, and we fixed it because it was just a bug, well, all the
124: better. Flaws have been found in just about every area of the system.
125: Entire new classes of security problems have been found during our
126: audit, and often source code which had been audited earlier needs
127: re-auditing with these new flaws in mind. Code often gets audited
128: multiple times, and by multiple people with different auditing
1.441 bentley 129: skills.
1.12 deraadt 130:
1.441 bentley 131: <p>
1.94 deraadt 132: Some members of our security auditing team worked for Secure Networks,
133: the company that made the industry's premier network security scanning
134: software package Ballista (Secure Networks got purchased by Network
135: Associates, Ballista got renamed to Cybercop Scanner, and well...)
136: That company did a lot of security research, and thus fit in well
1.106 deraadt 137: with the OpenBSD stance. OpenBSD passed Ballista's tests with flying
1.441 bentley 138: colours since day 1.
1.31 deraadt 139:
1.441 bentley 140: <p>
1.34 deraadt 141: Another facet of our security auditing process is its proactiveness.
1.45 deraadt 142: In most cases we have found that the determination of exploitability
143: is not an issue. During our ongoing auditing process we find many
144: bugs, and endeavor to fix them even though exploitability is not
145: proven. We fix the bug, and we move on to find other bugs to fix. We
146: have fixed many simple and obvious careless programming errors in code
147: and only months later discovered that the problems were in fact
148: exploitable. (Or, more likely someone on
1.439 tb 149: <a href="https://www.securityfocus.com/archive/1">BUGTRAQ</a>
1.441 bentley 150: would report that other operating systems were vulnerable to a <q>newly
151: discovered problem</q>, and then it would be discovered that OpenBSD had
1.45 deraadt 152: been fixed in a previous release). In other cases we have been saved
153: from full exploitability of complex step-by-step attacks because we
154: had fixed one of the intermediate steps. An example of where we
1.94 deraadt 155: managed such a success is the lpd advisory that Secure Networks put out.
1.29 deraadt 156:
1.441 bentley 157: <li><h3 id=newtech>New Technologies</h3>
1.278 deraadt 158:
1.441 bentley 159: <p>
1.278 deraadt 160: As we audit source code, we often invent new ways of solving problems.
161: Sometimes these ideas have been used before in some random application
162: written somewhere, but perhaps not taken to the degree that we do.
163:
164: <ul>
165: <li>strlcpy() and strlcat()
166: <li>Memory protection purify
167: <ul>
168: <li>W^X
169: <li>.rodata segment
170: <li>Guard pages
171: <li>Randomized malloc()
172: <li>Randomized mmap()
173: <li>atexit() and stdio protection
174: </ul>
1.295 otto 175: <li>Privilege separation
1.278 deraadt 176: <li>Privilege revocation
177: <li>Chroot jailing
178: <li>New uids
179: <li>ProPolice
1.424 tb 180: <li>... <a href="/innovations.html">and others</a>
1.278 deraadt 181: </ul>
182:
1.441 bentley 183: <li><h3 id=reward>The Reward</h3>
1.106 deraadt 184:
1.441 bentley 185: <p>
1.45 deraadt 186: Our proactive auditing process has really paid off. Statements like
1.441 bentley 187: <q>This problem was fixed in OpenBSD about 6 months ago</q> have become
1.45 deraadt 188: commonplace in security forums like
1.441 bentley 189: <a href="https://www.securityfocus.com/archive/1">BUGTRAQ</a>.
1.35 deraadt 190:
1.441 bentley 191: <p>
1.45 deraadt 192: The most intense part of our security auditing happened immediately
1.441 bentley 193: before the OpenBSD 2.0 release and during the 2.0→2.1 transition,
1.45 deraadt 194: over the last third of 1996 and first half of 1997. Thousands (yes,
195: thousands) of security issues were fixed rapidly over this year-long
196: period; bugs like the standard buffer overflows, protocol
197: implementation weaknesses, information gathering, and filesystem
198: races. Hence most of the security problems that we encountered were
199: fixed before our 2.1 release, and then a far smaller number needed
200: fixing for our 2.2 release. We do not find as many problems anymore,
201: it is simply a case of diminishing returns. Recently the security
202: problems we find and fix tend to be significantly more obscure or
1.441 bentley 203: complicated. Still we will persist for a number of reasons:
1.36 deraadt 204:
1.35 deraadt 205: <ul>
1.45 deraadt 206: <li>Occasionally we find a simple problem we missed earlier. Doh!
1.35 deraadt 207: <li>Security is like an arms race; the best attackers will continue
1.45 deraadt 208: to search for more complicated exploits, so we will too.
209: <li>Finding and fixing subtle flaws in complicated software is
210: a lot of fun.
1.35 deraadt 211: </ul>
1.441 bentley 212:
1.106 deraadt 213: <p>
1.14 deraadt 214: The auditing process is not over yet, and as you can see we continue
1.441 bentley 215: to find and fix new security flaws.
1.12 deraadt 216:
1.441 bentley 217: <li><h3 id=default><q>Secure by Default</q></h3>
1.106 deraadt 218:
1.441 bentley 219: <p>
1.106 deraadt 220: To ensure that novice users of OpenBSD do not need to become security
221: experts overnight (a viewpoint which other vendors seem to have), we
222: ship the operating system in a Secure by Default mode. All non-essential
223: services are disabled. As the user/administrator becomes more familiar
224: with the system, he will discover that he has to enable daemons and other
225: parts of the system. During the process of learning how to enable a new
1.441 bentley 226: service, the novice is more likely to learn of security considerations.
1.106 deraadt 227:
1.441 bentley 228: <p>
1.106 deraadt 229: This is in stark contrast to the increasing number of systems that
230: ship with NFS, mountd, web servers, and various other services enabled
231: by default, creating instantaneous security problems for their users
1.441 bentley 232: within minutes after their first install.
1.106 deraadt 233:
1.441 bentley 234: <li><h3 id=crypto>Cryptography</h3>
1.106 deraadt 235:
1.441 bentley 236: <p>
1.106 deraadt 237: And of course, since the OpenBSD project is based in Canada, it is possible
238: for us to integrate cryptography. For more information, read the page
1.441 bentley 239: outlining <a href=crypto.html>what we have done with cryptography</a>.
1.106 deraadt 240:
1.441 bentley 241: <li><h3 id=advisories>Advisories</h3>
1.106 deraadt 242:
1.441 bentley 243: <p>
1.418 tedu 244: Please refer to the links at the top of this page.
1.106 deraadt 245:
1.441 bentley 246: <li><h3 id=watching>Watching our Changes</h3>
1.106 deraadt 247:
1.441 bentley 248: <p>
1.21 deraadt 249: Since we take a proactive stance with security, we are continually
250: finding and fixing new security problems. Not all of these problems
1.80 espie 251: get widely reported because (as stated earlier) many of them are not
1.45 deraadt 252: confirmed to be exploitable; many simple bugs we fix do turn out to
253: have security consequences we could not predict. We do not have the
1.441 bentley 254: time resources to make these changes available in the above format.
1.21 deraadt 255:
1.441 bentley 256: <p>
1.21 deraadt 257: Thus there are usually minor security fixes in the current source code
258: beyond the previous major OpenBSD release. We make a limited
1.45 deraadt 259: guarantee that these problems are of minimal impact and unproven
1.44 ian 260: exploitability. If we discover that a problem definitely matters for
1.441 bentley 261: security, patches will show up here <strong>VERY</strong> quickly.
1.21 deraadt 262:
1.441 bentley 263: <p>
1.45 deraadt 264: People who are really concerned with security can do a number of
1.441 bentley 265: things:
1.21 deraadt 266:
267: <ul>
268: <li>If you understand security issues, watch our
1.294 david 269: <a href="mail.html">source-changes mailing list</a> and keep an
1.23 deraadt 270: eye out for things which appear security related. Since
1.21 deraadt 271: exploitability is not proven for many of the fixes we make,
1.441 bentley 272: do not expect the relevant commit message to say <q>SECURITY FIX!</q>.
1.21 deraadt 273: If a problem is proven and serious, a patch will be available
274: here very shortly after.
275: <li>Track our current source code tree, and teach yourself how to do a
1.29 deraadt 276: complete system build from time to time (read /usr/src/Makefile
277: carefully). Users can make the assumption that the current
278: source tree always has stronger security than the previous release.
1.45 deraadt 279: However, building your own system from source code is not trivial;
1.424 tb 280: it is over 850MB of source code, and problems do occur as we
1.45 deraadt 281: transition between major releases.
1.115 ericj 282: <li>Install a binary snapshot for your
1.80 espie 283: architecture, which are made available fairly often. For
1.424 tb 284: instance, an amd64 snapshot is typically made available daily.
1.21 deraadt 285: </ul>
286:
1.441 bentley 287: <li><h3 id=reporting>Reporting problems</h3>
288:
1.9 deraadt 289: <p>
1.441 bentley 290: If you find a new security problem, you can mail it to
1.294 david 291: <a href="mailto:deraadt@openbsd.org">deraadt@openbsd.org</a>.
1.7 deraadt 292: <br>
1.5 deraadt 293: If you wish to PGP encode it (but please only do so if privacy is very
1.112 philen 294: urgent, since it is inconvenient) use this <a href="advisories/pgpkey.txt">pgp key</a>.
1.5 deraadt 295:
1.441 bentley 296: <li><h3 id=papers>Further Reading</h3>
297:
1.107 deraadt 298: <p>
1.389 lum 299: Numerous
1.441 bentley 300: <a href="events.html">papers</a> have been written by OpenBSD team members,
1.389 lum 301: many dedicated to security.
1.294 david 302: </ul>
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