CVE-2021-44228 vulnerability Log4j (Solr)? #4375

gaetandezeiraud · 2021-12-11T10:27:59Z

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I understand that not following or deleting the below instructions will result in immediate closure and/or deletion of my issue.
I have understood that this bug report is dedicated for bugs, and not for support-related inquiries.
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Summary

Mailcow is vulnerable to CVE-2021-44228 Log4j?
https://community.mailcow.email/d/1229-cve-2021-44228-vulnerability-solr

The text was updated successfully, but these errors were encountered:

andryyy · 2021-12-11T10:31:23Z

How exactly can we access Solr from outside? Mit besten Grüßen André Peters

…

Am 11.12.2021 um 11:28 schrieb DEZEIRAUD Gaëtan ***@***.***>: Prior to placing the issue, please check following: (fill out each checkbox with an X once done) I understand that not following or deleting the below instructions will result in immediate closure and/or deletion of my issue. I have understood that this bug report is dedicated for bugs, and not for support-related inquiries. I have understood that answers are voluntary and community-driven, and not commercial support. I have verified that my issue has not been already answered in the past. I also checked previous issues. Summary Mailcow is vulnerable to CVE-2021-44228 Log4j? https://community.mailcow.email/d/1229-cve-2021-44228-vulnerability-solr — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

gaetandezeiraud · 2021-12-11T10:36:21Z

Don't know. It is more a question about if mailcow is potentially vulnerable or not.
By security, I have shutdown my mail servers until I get an answer.

andryyy · 2021-12-11T10:45:53Z

You are fine. Images should be updated asap anyway.

…

Am 11.12.2021 um 11:36 schrieb DEZEIRAUD Gaëtan ***@***.***>: Don't know. It is more a question about if mailcow is potentially vulnerable or not. By security, I have shutdown my mail servers until I get an answer. — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or unsubscribe.

andryyy · 2021-12-11T15:53:15Z

theoretically trivial

How?

MAGICCC · 2021-12-11T16:04:49Z

Seems Solr doesnt even have an update ready on their site: https://solr.apache.org/downloads.html
And they claim that 8.11.1 is safe: https://solr.apache.org/security.html#apache-solr-affected-by-apache-log4j-cve-2021-44228

Either way: We need to update to 8.x sooner or later since this is their stable release for now.

gaetandezeiraud · 2021-12-11T16:36:20Z

apache/solr#454

gaetandezeiraud · 2021-12-11T16:46:07Z

theoretically trivial

How?

It is enough that a bad string is sent somewhere and which arrives to solr which logs it and it is finished. Code execution.

jonprocter · 2021-12-11T19:44:43Z

I've just disabled Solr on my mailcow servers to mitigate any potential risk from this, and everything seems to be working to the point I don't even know if to bother turning it back on when it's fixed (for reference for anybody reading who isn't sure: set SKIP_SOLR=y in mailcow.conf, line 143 for me, and then run docker-compose up -d)

marc1006 · 2021-12-11T20:24:31Z

An easy workaround would be to use the "fix/workaround" suggested in apache/solr#454 (comment)
(adding SOLR_OPTS="$SOLR_OPTS -Dlog4j2.formatMsgNoLookups=true").

gaetandezeiraud · 2021-12-11T20:35:24Z

@marc1006 Can you write an explanation of how to do this? Step by step.

marc1006 · 2021-12-11T20:44:29Z

At best, this should be fixed in the solr image used by Mailcow by the maintainer of Mailcow. Probably by either adapting this file https://github.com/mailcow/mailcow-dockerized/blob/master/data/Dockerfiles/solr/solr.sh or the Dockerfile https://github.com/mailcow/mailcow-dockerized/blob/master/data/Dockerfiles/solr/Dockerfile

Note: I'm not familiar with the Mailcow code base.

@Brouilles
Please perform the steps below only if you know what you're doing (and have a backup)

Edit the file data/Dockerfiles/solr/solr.sh (https://github.com/mailcow/mailcow-dockerized/blob/master/data/Dockerfiles/solr/solr.sh)
e.g.

...
if [[ "${1}" == "--bootstrap" ]]; then
  echo "Creating initial configuration"
  ### ADD THE LINE BELOW
  echo 'SOLR_OPTS="$SOLR_OPTS -Dlog4j2.formatMsgNoLookups=true"' >> /opt/solr/bin/solr.in.sh
  ###
  echo "Modifying default config set"
  ...

Build the docker image (and tag it as mailcow/solr:tmpfix)
e.g.
# docker build data/Dockerfiles/solr -t mailcow/solr:tmpfix
Adapt docker-compose.yml so our newly created docker image is used

...
    solr-mailcow:
      image: mailcow/solr:tmpfix
...

Restart Mailcow
# docker-compose up -d

Once there is a fix in Mailcow, you will need to revert/undo the changes I suggested (and delete the mailcow/solr:tmpfix docker image) before updating Mailcow!!!!

gaetandezeiraud · 2021-12-11T20:49:03Z

Thanks @jonprocter I have do the same.

yoyellow · 2021-12-12T11:41:47Z

e1db347

is pushed. am i correct in assuming that this resolves the vulnerability CVE-2021-44228 @andryyy

andryyy · 2021-12-12T12:58:08Z

The Solr vulnerability was fixed, yes.

mailcow was never directly affected.

gaetandezeiraud · 2021-12-12T16:03:19Z

The Solr vulnerability was fixed, yes.

mailcow was never directly affected.

I am not so sure. https://twitter.com/gossithedog/status/1469993248559140864?s=21

andryyy · 2021-12-12T16:16:33Z

WTF? Why are you spreading this crap? What is wrong with you? It was not affected. Post how you exploit it or stfu. Sigh.

…

Am 12.12.2021 um 17:03 schrieb DEZEIRAUD Gaëtan ***@***.***>: The Solr vulnerability was fixed, yes. mailcow was never directly affected. I am not so sure. https://twitter.com/gossithedog/status/1469993248559140864?s=21 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

jonprocter · 2021-12-12T16:25:06Z

The Solr vulnerability was fixed, yes.

mailcow was never directly affected.

that's great, thanks!

fluxens · 2021-12-12T16:53:25Z

Checking solr.log in the solr container reveals that every search via the UI is logged verbatim:

webapp=/solr path=/select params={q={!lucene+q.op%3DAND}subject:exploit_goes_here+OR+from:exploit_goes_here&fl=uid,score&sort=uid+asc&fq=%2Bbox:35007c1e32358461310200006dabb843+%2Buser:[email protected]&rows=14&wt=xml} hits=0 status=0 QTime=4

solr uses log4j, so I would not say that it is not affected at all.

PH89 · 2021-12-12T21:36:15Z

@andryyy Could you gave some details how is was fixed ? Because your Solr docker images still uses version 7.7.3.
Just updating the image from 1.7 to 1.8 is not providing enough information.

fluxens · 2021-12-12T21:46:39Z

I was curious myself, so I compared 1.7 and 1.8:

/opt/docker-solr/scripts/start-local-solr

-MY_SOLR_OPTS="${MY_SOLR_OPTS:-} -Djetty.host=${SOLR_LOCAL_HOST:-localhost}"
+MY_SOLR_OPTS="${MY_SOLR_OPTS:-} -Djetty.host=${SOLR_LOCAL_HOST:-localhost} -Dlog4j2.formatMsgNoLookups=true"

/opt/docker-solr/scripts/solr-fg

+EXTRA_ARGS+=('-Dlog4j2.formatMsgNoLookups=true')

MAGICCC · 2021-12-12T21:49:33Z

It uses this patch now: docker-solr/docker-solr@74d04b4

digitalkram · 2021-12-12T21:52:08Z

1.8 uses jvm property "-Dlog4j2.formatMsgNoLookups=true" so it should be safe

EDIT: blargh. I was too slow 😉 Sorry for basically repeating the contentof the two previous posts 😓

PH89 · 2021-12-12T21:54:01Z

Okay I can confirm that setting is set. 👍🏻

tacerus · 2021-12-14T20:55:18Z

Ah yes, the classic "it's not an issue til it becomes an issue".

k00b0ld · 2021-12-15T02:19:18Z

Latest insight: to set the system property Dlog4j2.formatMsgNoLookups to true do NOT mitigate this specific vulnerability

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-45046

MAGICCC · 2021-12-15T05:59:30Z

Yep indeed, but solr is still not affected:

Re: Log4j < 2.15.0 may still be vulnerable even if -Dlog4j2.formatMsgNoLookups=true is set
The MDC Patterns used by solr are for the collection, shard, replica, core
and node names, and a potential trace id. All of those are restricted to
alphanumeric, no special characters like $ or { needed for the injection.
And trying to access a collection that didn’t exist Returns 404 without
logging.
Upgrading is always going to be more complete, but I think we’re still ok
for now, at least until the next iteration of this attack surfaces.

docker-solr/docker-solr#397 (comment)

sebiboga · 2021-12-15T19:07:37Z

well... you can use:

[Windows] set "START_OPTS=%START_OPTS% -Dlog4j2.formatMsgNoLookups=true"
(in file solr.cmd from \bin folder)

[Linux] update SOLR_START_OPTS=(...) adding "-Dlog4j2.formatMsgNoLookups=true" whereever you want inside brackets
(in file solr from /bin folder)

gaetandezeiraud added the bug label Dec 11, 2021

gaetandezeiraud closed this as completed Dec 12, 2021

gaetandezeiraud reopened this Dec 12, 2021

MAGICCC closed this as completed Dec 13, 2021

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CVE-2021-44228 vulnerability Log4j (Solr)? #4375

CVE-2021-44228 vulnerability Log4j (Solr)? #4375

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CVE-2021-44228 vulnerability Log4j (Solr)? #4375

CVE-2021-44228 vulnerability Log4j (Solr)? #4375

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