Error: SSL_accept() syscall failed

C. James Ervin jervin at kites.org
Fri Oct 11 14:38:36 EEST 2019


In case it helps, here are the results of testssl.sh:


jervin at MiniUntu:~/testssl/testssl.sh$ ./testssl.sh kumo.kites.org:993

###########################################################
     testssl.sh       3.0rc5 from https://testssl.sh/dev/
     (35c69be 2019-10-02 17:53:37 -- )

       This program is free software. Distribution and
              modification under GPLv2 permitted.
       USAGE w/o ANY WARRANTY. USE IT AT YOUR OWN RISK!

        Please file bugs @ https://testssl.sh/bugs/

###########################################################

  Using "OpenSSL 1.0.2-chacha (1.0.2k-dev)" [~183 ciphers]
  on MiniUntu:./bin/openssl.Linux.x86_64
  (built: "Jan 18 17:12:17 2019", platform: "linux-x86_64")


  Start 2019-10-11 07:28:20        -->> 3.222.54.62:993 (kumo.kites.org) 
<<--

  rDNS (3.222.54.62):     kumo.kites.org.
  Service detected:       IMAP, thus skipping HTTP specific checks


  Testing protocols via sockets except NPN+ALPN

  SSLv2      not offered (OK)
  SSLv3      not offered (OK)
  TLS 1      offered (deprecated)
  TLS 1.1    offered (deprecated)
  TLS 1.2    offered (OK)
  TLS 1.3    offered (OK): final
  NPN/SPDY   not offered
  ALPN/HTTP2 not offered

  Testing cipher categories

  NULL ciphers (no encryption)                  not offered (OK)
  Anonymous NULL Ciphers (no authentication)    not offered (OK)
  Export ciphers (w/o ADH+NULL)                 not offered (OK)
  LOW: 64 Bit + DES, RC[2,4] (w/o export)       not offered (OK)
  Triple DES Ciphers / IDEA                     not offered (OK)
  Average: SEED + 128+256 Bit CBC ciphers       offered
  Strong encryption (AEAD ciphers)              offered (OK)


  Testing robust (perfect) forward secrecy, (P)FS -- omitting Null 
Authentication/Encryption, 3DES, RC4

  PFS is offered (OK)          TLS_AES_256_GCM_SHA384 
TLS_CHACHA20_POLY1305_SHA256
                               ECDHE-RSA-AES256-GCM-SHA384 
ECDHE-RSA-AES256-SHA384 ECDHE-RSA-AES256-SHA
                               DHE-RSA-AES256-GCM-SHA384 
ECDHE-RSA-CHACHA20-POLY1305
                               DHE-RSA-CHACHA20-POLY1305 
DHE-RSA-AES256-CCM8 DHE-RSA-AES256-CCM
                               DHE-RSA-AES256-SHA256 DHE-RSA-AES256-SHA 
ECDHE-RSA-CAMELLIA256-SHA384
                               DHE-RSA-CAMELLIA256-SHA256 
DHE-RSA-CAMELLIA256-SHA
                               DHE-RSA-ARIA256-GCM-SHA384 
ECDHE-ARIA256-GCM-SHA384
                               TLS_AES_128_GCM_SHA256 
ECDHE-RSA-AES128-GCM-SHA256
                               ECDHE-RSA-AES128-SHA256 
ECDHE-RSA-AES128-SHA DHE-RSA-AES128-GCM-SHA256
                               DHE-RSA-AES128-CCM8 DHE-RSA-AES128-CCM 
DHE-RSA-AES128-SHA256
                               DHE-RSA-AES128-SHA 
ECDHE-RSA-CAMELLIA128-SHA256
                               DHE-RSA-CAMELLIA128-SHA256 
DHE-RSA-SEED-SHA DHE-RSA-CAMELLIA128-SHA
                               DHE-RSA-ARIA128-GCM-SHA256 
ECDHE-ARIA128-GCM-SHA256
  Elliptic curves offered:     secp384r1
  DH group offered:            Unknown DH group (1024 bits)

  Testing server preferences

  Has server cipher order?     yes (OK) -- only for < TLS 1.3
  Negotiated protocol          TLSv1.3
  Negotiated cipher            TLS_AES_256_GCM_SHA384, 384 bit ECDH (P-384)
  Cipher order
     TLSv1:     ECDHE-RSA-AES256-SHA DHE-RSA-AES256-SHA 
DHE-RSA-CAMELLIA256-SHA AES256-SHA
                CAMELLIA256-SHA ECDHE-RSA-AES128-SHA DHE-RSA-AES128-SHA 
DHE-RSA-SEED-SHA
                DHE-RSA-CAMELLIA128-SHA AES128-SHA SEED-SHA CAMELLIA128-SHA
     TLSv1.1:   ECDHE-RSA-AES256-SHA DHE-RSA-AES256-SHA 
DHE-RSA-CAMELLIA256-SHA AES256-SHA
                CAMELLIA256-SHA ECDHE-RSA-AES128-SHA DHE-RSA-AES128-SHA 
DHE-RSA-SEED-SHA
                DHE-RSA-CAMELLIA128-SHA AES128-SHA SEED-SHA CAMELLIA128-SHA
     TLSv1.2:   ECDHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-AES256-SHA384 
ECDHE-RSA-AES256-SHA
                DHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-CHACHA20-POLY1305 
DHE-RSA-CHACHA20-POLY1305
                DHE-RSA-AES256-CCM8 DHE-RSA-AES256-CCM 
DHE-RSA-AES256-SHA256 DHE-RSA-AES256-SHA
                ECDHE-RSA-CAMELLIA256-SHA384 DHE-RSA-CAMELLIA256-SHA256 
DHE-RSA-CAMELLIA256-SHA
                AES256-GCM-SHA384 AES256-CCM8 AES256-CCM AES256-SHA256 
AES256-SHA CAMELLIA256-SHA256
                CAMELLIA256-SHA ARIA256-GCM-SHA384 
DHE-RSA-ARIA256-GCM-SHA384 ECDHE-ARIA256-GCM-SHA384
                ECDHE-RSA-AES128-GCM-SHA256 ECDHE-RSA-AES128-SHA256 
ECDHE-RSA-AES128-SHA
                DHE-RSA-AES128-GCM-SHA256 DHE-RSA-AES128-CCM8 
DHE-RSA-AES128-CCM AES128-CCM8 AES128-CCM
                DHE-RSA-AES128-SHA256 DHE-RSA-AES128-SHA 
ECDHE-RSA-CAMELLIA128-SHA256
                DHE-RSA-CAMELLIA128-SHA256 DHE-RSA-SEED-SHA 
DHE-RSA-CAMELLIA128-SHA AES128-GCM-SHA256
                AES128-SHA256 AES128-SHA CAMELLIA128-SHA256 SEED-SHA 
CAMELLIA128-SHA ARIA128-GCM-SHA256
                DHE-RSA-ARIA128-GCM-SHA256 ECDHE-ARIA128-GCM-SHA256
     TLSv1.3:   TLS_AES_256_GCM_SHA384 TLS_CHACHA20_POLY1305_SHA256 
TLS_AES_128_GCM_SHA256


  Testing server defaults (Server Hello)

  TLS extensions (standard)    "renegotiation info/#65281" "server 
name/#0" "EC point formats/#11"
                               "session ticket/#35" "supported 
versions/#43" "key share/#51"
                               "max fragment length/#1" 
"encrypt-then-mac/#22"
                               "extended master secret/#23"
  Session Ticket RFC 5077 hint 7200 seconds, session tickets keys seems 
to be rotated < daily
  SSL Session ID support       yes
  Session Resumption           Tickets no, ID: no
  TLS clock skew               Random values, no fingerprinting possible
  Signature Algorithm          SHA256 with RSA
  Server key size              RSA 2048 bits
  Server key usage             Digital Signature, Key Encipherment
  Server extended key usage    TLS Web Server Authentication, TLS Web 
Client Authentication
  Serial / Fingerprints F451FC38110BD0CC08D03E6975C05AC0 / SHA1 
5EB402C1FB4020C1697E48931F68D11145D48F43
                               SHA256 
C37816C37E38DAEF4758EC41EA9F332C08C9310CA63976BD5A294EE7D84B3CF0
  Common Name (CN)             kumo.kites.org
  subjectAltName (SAN)         kumo.kites.org www.kumo.kites.org
  Issuer                       Sectigo RSA Domain Validation Secure 
Server CA (Sectigo Limited from GB)
  Trust (hostname)             Ok via SAN and CN (same w/o SNI)
  Chain of trust               Ok
  EV cert (experimental)       no
  ETS/"eTLS", visibility info  not present
  Certificate Validity (UTC)   364 >= 60 days (2019-10-10 20:00 --> 
2020-10-09 19:59)
  # of certificates provided   6 (certificate list ordering problem)
  Certificate Revocation List  --
  OCSP URI                     http://ocsp.sectigo.com
  OCSP stapling                not offered
  OCSP must staple extension   --
  DNS CAA RR (experimental)    not offered
  Certificate Transparency     yes (certificate extension)


  Testing vulnerabilities

  Heartbleed (CVE-2014-0160)                not vulnerable (OK), no 
heartbeat extension
  CCS (CVE-2014-0224)                       not vulnerable (OK)
  Ticketbleed (CVE-2016-9244), experiment.  -- (applicable only for HTTPS)
  ROBOT                                     not vulnerable (OK)
  Secure Renegotiation (RFC 5746)           supported (OK)
  Secure Client-Initiated Renegotiation     not vulnerable (OK)
  CRIME, TLS (CVE-2012-4929)                not vulnerable (OK) (not 
using HTTP anyway)
  POODLE, SSL (CVE-2014-3566)               not vulnerable (OK)
  TLS_FALLBACK_SCSV (RFC 7507)              Downgrade attack prevention 
supported (OK)
  SWEET32 (CVE-2016-2183, CVE-2016-6329)    not vulnerable (OK)
  FREAK (CVE-2015-0204)                     not vulnerable (OK)
  DROWN (CVE-2016-0800, CVE-2016-0703)      not vulnerable on this host 
and port (OK)
                                            make sure you don't use this 
certificate elsewhere with SSLv2 enabled services
https://censys.io/ipv4?q=C37816C37E38DAEF4758EC41EA9F332C08C9310CA63976BD5A294EE7D84B3CF0 
could help you to find out
  LOGJAM (CVE-2015-4000), experimental      not vulnerable (OK): no DH 
EXPORT ciphers
                                            But: Unknown DH group (1024 
bits)
  BEAST (CVE-2011-3389)                     TLS1: ECDHE-RSA-AES256-SHA 
DHE-RSA-AES256-SHA
DHE-RSA-CAMELLIA256-SHA AES256-SHA CAMELLIA256-SHA
ECDHE-RSA-AES128-SHA DHE-RSA-AES128-SHA
DHE-RSA-SEED-SHA DHE-RSA-CAMELLIA128-SHA AES128-SHA
                                                  SEED-SHA CAMELLIA128-SHA
                                            VULNERABLE -- but also 
supports higher protocols  TLSv1.1 TLSv1.2 (likely mitigated)
  LUCKY13 (CVE-2013-0169), experimental     potentially VULNERABLE, uses 
cipher block chaining (CBC) ciphers with TLS. Check patches
  RC4 (CVE-2013-2566, CVE-2015-2808)        no RC4 ciphers detected (OK)


  Testing 370 ciphers via OpenSSL plus sockets against the server, 
ordered by encryption strength

Hexcode  Cipher Suite Name (OpenSSL)       KeyExch. Encryption  Bits     
Cipher Suite Name (IANA/RFC)
-----------------------------------------------------------------------------------------------------------------------------
[redacted to reduce size]


  Running client simulations via sockets

  Android 8.1 (native)         TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256, 384 
bit ECDH (P-384)
  Android 9.0 (native)         TLSv1.3 TLS_AES_128_GCM_SHA256, 384 bit 
ECDH (P-384)
  Java 6u45                    TLSv1.0 AES128-SHA, No FS
  Java 7u25                    TLSv1.0 ECDHE-RSA-AES128-SHA, 384 bit 
ECDH (P-384)
  Java 8u161                   TLSv1.2 ECDHE-RSA-AES256-SHA384, 384 bit 
ECDH (P-384)
  Java 11.0.2 (OpenJDK)        TLSv1.3 TLS_AES_128_GCM_SHA256, 384 bit 
ECDH (P-384)
  Java 12.0.1 (OpenJDK)        TLSv1.3 TLS_AES_128_GCM_SHA256, 384 bit 
ECDH (P-384)
  OpenSSL 1.0.1l               TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 384 
bit ECDH (P-384)
  OpenSSL 1.0.2e               TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 384 
bit ECDH (P-384)
  OpenSSL 1.1.0j (Debian)      TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 384 
bit ECDH (P-384)
  OpenSSL 1.1.1b (Debian)      TLSv1.3 TLS_AES_256_GCM_SHA384, 384 bit 
ECDH (P-384)
  Thunderbird (60.6)           TLSv1.3 TLS_AES_128_GCM_SHA256, 384 bit 
ECDH (P-384)

  Done 2019-10-11 07:31:08 [ 170s] -->> 3.222.54.62:993 (kumo.kites.org) 
<<--


On 10/11/19 7:22 AM, C. James Ervin via dovecot wrote:
>
> In setting up my new mail server, I am getting the following in the logs:
>
> Oct 11 07:10:59 kumo dovecot[5704]: imap-login: Disconnected (no auth 
> attempts in 0 secs): user=<>, rip=24.53.79.10, lip=172.26.12.90, *TLS 
> handshaking: SSL_accept() syscall failed: Success*, 
> session=<B9OokqCUD+UYNU8K>
>
>
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