[Oisf-devel] File MD5 inconsistent checksums.
Victor Julien
victor at inliniac.net
Thu Jul 12 07:16:30 UTC 2012
On 07/12/2012 08:27 AM, Nikolay Denev wrote:
>
> On Jul 12, 2012, at 9:25 AM, Nikolay Denev wrote:
>
>> On Jul 12, 2012, at 9:03 AM, Nikolay Denev wrote:
>>
>>> Hi,
>>>
>>> I'm seeing some strange behaviour while testing the filemd5 and md5 checksumming in general.
>>>
>>> I have a server which serves a file over http and the server port on the switch is mirrored to a box running suricata.
>>>
>>> I have the md5 of the file as it is on the server : c2ddef96c8a1aeddf316ff3cba37f318
>>> When I do a curl download and pipe it to md5 the checksum matches.
>>>
>>> :~ ndenev$ curl http://testserver.example.com/test.img | md5
>>> % Total % Received % Xferd Average Speed Time Time Time Current
>>> Dload Upload Total Spent Left Speed
>>> 100 117k 100 117k 0 0 1744k 0 --:--:-- --:--:-- --:--:-- 1933k
>>> c2ddef96c8a1aeddf316ff3cba37f318
>>>
>>> However the filemd5 rule I've created never matches, and files-json.log shows completely different checksums, which also are not consistent?
>>> And the filesize too differs, and as I said the curl on the client machine gives the same md5 each time.
>>>
>>> { "timestamp": "07\/12\/2012-07:56:15.944637", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51135, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>>> { "timestamp": "07\/12\/2012-07:56:25.033265", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51136, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "4b9fda98fbee8f4afea75b7b466b2e1a", "stored": false, "size": 3839 }
>>> { "timestamp": "07\/12\/2012-07:56:30.232624", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51138, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>>> { "timestamp": "07\/12\/2012-07:56:35.410789", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51140, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>>> { "timestamp": "07\/12\/2012-07:56:39.225699", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51142, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>>>
>>>
>>> This is the latest entry in my stats.log :
>>>
>>> -------------------------------------------------------------------
>>> Date: 7/12/2012 -- 08:00:24 (uptime: 0d, 00h 11m 20s)
>>> -------------------------------------------------------------------
>>> Counter | TM Name | Value
>>> -------------------------------------------------------------------
>>> tcp.sessions | Detect | 11097
>>> tcp.ssn_memcap_drop | Detect | 0
>>> tcp.pseudo | Detect | 6762
>>> tcp.invalid_checksum | Detect | 22
>>> tcp.no_flow | Detect | 0
>>> tcp.reused_ssn | Detect | 0
>>> tcp.memuse | Detect | 72351744
>>> tcp.syn | Detect | 11520
>>> tcp.synack | Detect | 10973
>>> tcp.rst | Detect | 7998
>>> tcp.segment_memcap_drop | Detect | 0
>>> tcp.stream_depth_reached | Detect | 0
>>> tcp.reassembly_memuse | Detect | 156557860
>>> tcp.reassembly_gap | Detect | 3646
>>> detect.alert | Detect | 24
>>> decoder.pkts | RxPcapix01 | 7799419
>>> decoder.bytes | RxPcapix01 | 6619532090
>>> decoder.ipv4 | RxPcapix01 | 7732780
>>> decoder.ipv6 | RxPcapix01 | 181
>>> decoder.ethernet | RxPcapix01 | 7799419
>>> decoder.raw | RxPcapix01 | 0
>>> decoder.sll | RxPcapix01 | 0
>>> decoder.tcp | RxPcapix01 | 4036503
>>> decoder.udp | RxPcapix01 | 767312
>>> decoder.sctp | RxPcapix01 | 0
>>> decoder.icmpv4 | RxPcapix01 | 1957
>>> decoder.icmpv6 | RxPcapix01 | 0
>>> decoder.ppp | RxPcapix01 | 0
>>> decoder.pppoe | RxPcapix01 | 0
>>> decoder.gre | RxPcapix01 | 0
>>> decoder.vlan | RxPcapix01 | 15588470
>>> decoder.avg_pkt_size | RxPcapix01 | 849
>>> decoder.max_pkt_size | RxPcapix01 | 1518
>>> defrag.ipv4.fragments | RxPcapix01 | 0
>>> defrag.ipv4.reassembled | RxPcapix01 | 0
>>> defrag.ipv4.timeouts | RxPcapix01 | 0
>>> defrag.ipv6.fragments | RxPcapix01 | 0
>>> defrag.ipv6.reassembled | RxPcapix01 | 0
>>> defrag.ipv6.timeouts | RxPcapix01 | 0
>>> flow_mgr.closed_pruned | FlowManagerThread | 9036
>>> flow_mgr.new_pruned | FlowManagerThread | 3033
>>> flow_mgr.est_pruned | FlowManagerThread | 4478
>>> flow.memuse | FlowManagerThread | 5401024
>>> flow.spare | FlowManagerThread | 10034
>>> flow.emerg_mode_entered | FlowManagerThread | 0
>>> flow.emerg_mode_over | FlowManagerThread | 0
>>
>> I've now setup a rule to "filestore" the downloads so I can check them, and the stored files seem truncated.
>>
>> Also files-json.log continues to log "stored: false" while the files are actually saved.
>>
>>
>
> The file on the server is about 120K, but the saved files are about 4K.
> Which also reminds me that I've never actually saw a file much bigger than a few KBs in my files dir.
Did you try increasing your request-body-limit and response-body-limit?
https://redmine.openinfosecfoundation.org/projects/suricata/wiki/File_Extraction#Settings
The fact that the state is "closed" looks like a bug btw.
--
---------------------------------------------
Victor Julien
http://www.inliniac.net/
PGP: http://www.inliniac.net/victorjulien.asc
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