Aki Tuomi
2019-Aug-28 12:10 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
Dear subscribers, we have been made aware of critical vulnerability in
Dovecot and Pigeonhole.
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Open-Xchange Security Advisory 2019-08-14
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Product: Dovecot
Vendor: OX Software GmbH
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Internal reference: DOV-3278
Vulnerability type: Improper input validation (CWE-20)
Vulnerable version: All versions prior to 2.3.7.2 and 2.2.36.4
Vulnerable component: IMAP and ManageSieve protocol parsers (before and
after login)
Report confidence: Confirmed
Solution status: Fixed by Vendor
Fixed version: 2.3.7.2, 2.2.36.4
Researcher credits: Nick Roessler and Rafi Rubin, University of Pennsylvania
Vendor notification: 2019-04-13
Solution date: 2019-06-05
Public disclosure: 2019-08-28
CVE reference: CVE-2019-11500
CVSS: 8.1 (CVSS3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
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Vulnerability Details:
IMAP and ManageSieve protocol parsers do not properly handle NUL byte
when scanning data in quoted strings, leading to out of bounds heap
memory writes.
Risk:
This vulnerability allows for out-of-bounds writes to objects stored on
the heap up to 8096 bytes in pre-login phase, and 65536 bytes post-login
phase, allowing sufficiently skilled attacker to perform complicated
attacks that can lead to leaking private information or remote code
execution. Abuse of this bug is very difficult to observe, as it does
not necessarily cause a crash. Attempts to abuse this bug are not
directly evident from logs.
Steps to reproduce:
This bug is best observed using valgrind to see the out of bounds read
with following snippet:
perl -e 'print "a id (\"foo\"
\"".("x"x1021)."\\A\" \"bar\"
\"\000".("x"x1020)."\\A\")\n"' | nc
localhost 143
Solution:
Operators should update to the latest Patch Release. There is no
workaround for the issue.
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Aki Tuomi
Open-Xchange oy
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Christoph Pleger
2019-Aug-28 13:58 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
Hello, On 2019-08-28 14:10, Aki Tuomi via dovecot wrote:> Dear subscribers, we have been made aware of critical vulnerability in > Dovecot and Pigeonhole.Has this already been fixed in 2.2.36.4? Changelog does not mention it. Regards Christoph
Aki Tuomi
2019-Aug-28 14:03 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
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On 28/08/2019 16:58 Christoph Pleger via dovecot <
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Hello,
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On 2019-08-28 14:10, Aki Tuomi via dovecot wrote:
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Dear subscribers, we have been made aware of critical vulnerability in
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Dovecot and Pigeonhole.
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Has this already been fixed in 2.2.36.4? Changelog does not mention it.
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https://dovecot.org/pipermail/dovecot-news/2019-August/000416.html
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Aki Tuomi</pre>
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Giles Coochey
2019-Aug-28 15:38 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
On 28/08/2019 14:58, Christoph Pleger via dovecot wrote:> Hello, > > On 2019-08-28 14:10, Aki Tuomi via dovecot wrote: >> Dear subscribers, we have been made aware of critical vulnerability in >> Dovecot and Pigeonhole. > > Has this already been fixed in 2.2.36.4? Changelog does not mention it. >Solution status: Fixed by Vendor Fixed version: 2.3.7.2, 2.2.36.4> Regards > ? Christoph-- Giles Coochey
Christian Balzer
2019-Aug-30 08:00 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
Hello, Cc'ing Apollon in hopes he might have some insight here. When upgrading on Debian Stretch with the security fix packages all dovecot processes get killed and then restarted despite having "shutdown_clients = no" set. My guess would be a flaw in the upgrade procedure and/or unit files doing a stop and start when the new imapd package is installed. Can anybody think of a quick workaround or fix for this, as it's clearly not intended behavior (nor needed for this issue). Thanks, Christian -- Christian Balzer Network/Systems Engineer chibi at gol.com Rakuten Mobile Inc.
Daniel Lange
2019-Aug-30 15:38 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
Am 30.08.19 um 10:00 schrieb Christian Balzer via dovecot:> When upgrading on Debian Stretch with the security fix packages all > dovecot processes get killed and then restarted despite having > "shutdown_clients = no" set.This is systemd doing its "magic" (kill all control group processes), see https://dovecot.org/pipermail/dovecot/2016-June/104546.html for a potential fix.
KSB
2019-Sep-03 19:32 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
On 2019.08.28. 15:10, Aki Tuomi via dovecot wrote:> > Steps to reproduce: > > This bug is best observed using valgrind to see the out of bounds read > with following snippet: > > perl -e 'print "a id (\"foo\" \"".("x"x1021)."\\A\" \"bar\" > \"\000".("x"x1020)."\\A\")\n"' | nc localhost 143 > >Hi! Before I had 2.2.25 and returned result was: * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready. a BAD Missing ')' now I upgraded to 2.2.36.4 and the result is the same. -- KSB
KSB
2019-Sep-03 22:22 UTC
CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
On 2019.09.03. 22:32, KSB via dovecot wrote:> On 2019.08.28. 15:10, Aki Tuomi via dovecot wrote: >> >> Steps to reproduce: >> >> This bug is best observed using valgrind to see the out of bounds read >> with following snippet: >> >> perl -e 'print "a id (\"foo\" \"".("x"x1021)."\\A\" \"bar\" >> \"\000".("x"x1020)."\\A\")\n"' | nc localhost 143 >> >> > > Hi! > Before I had 2.2.25 and returned result was: > * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE > IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready. > a BAD Missing ')' > > now I upgraded to 2.2.36.4 and the result is the same. > > -- > KSBBtw, got 1 time: perl -e 'print "a id (\"foo\" \"".("x"x1021)."\\A\" \"bar\" \"\000".("x"x1020)."\\A\")\n"' | nc localhost 143 * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready. a BAD Missing ')' * BYE Input buffer full, aborting with 2.2.36.4 -- KSB
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