Building PostgreSQL old version from source to test vulnerability CVE-2017-7546

Hello.

I'm trying to build a vulnerable PostgreSQL system in a Docker container in
order to be able to exploit this vulnerability
<http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-7546>. I'm testing
with a C# app which simply connects using a *connstring* through
*npgsql *driver
(this is one of the vulnerable drivers
<https://wiki.postgresql.org/wiki/List_of_drivers> since it's not based on
*libpq*):

string connstring = String.Format("Server={0};Port={1};" +
"User
Id={2};Password={3};Database={4};PersistSecurityInfo=true",
//"10.5.0.73", "10005", "postgres", //Docker inside
Linux Mint's VM with port mapped like "docker run -p 10005:5432 ..."
//"10.5.0.73", "5432", "postgres", //Linux Mint's VM
"10.5.0.163", "5432", "postgres", //Ubuntu server's VM
"", "postgres");

*I've been able to exploit it in my Linux Mint VM* building from this commit
<https://github.com/postgres/postgres/commit/dec6e4746d2f82abc4f611797df65be5329b2b57>,
which is the parent of the commit which introduces the fix
<https://github.com/postgres/postgres/commit/d5d46d99ba47f> for the
vulnerability, but I couldn't do it either:

1. Building from *the same commit* zip file in another VM (Ubuntu
server).
2. Using DockerHub <https://hub.docker.com/r/library/postgres/tags/>'s
versions *which are expected to be vulnerable* (like 9.2.20, 9.6.3 and
9.6.2).
3. With a custom Docker container based on *debian:jessie* (also tried
with ubuntu:latest).

I've checked the ports I use are not conflicting with ports from another
proccess in any of those systems:

sudo lsof -i -P -n | grep LISTEN

and I've checked they all have these configurations:

/usr/local/pgsql/data/*pg_hba.conf*: host all all all password (This
is the *last
line*, and I also tried with *md5*).

/usr/local/pgsql/data/*postgresql.conf*: listen_addresses = '*'

I'm actually completely sure I'm connecting to the postgres instance I
expect, since the responses make complete sense when I adjust the config or
shut down the instances, except for those with empty passwords which should
log in successfully, but throw this exception instead:

No password has been provided but the backend requires one (in plaintext)

(Changing plaintext to md5 when I change pg_hba.conf's config).

It looks like the version I'm using is patched but it makes no sense why
the hell I could exploit it in my Linux Mint VM and I can't in my Ubuntu
Server VM, since I'm using the *exact same commit*. Regarding Docker
official images, they are 7 and 9 months old, which is before 7th August
(the day the patch came in), so I can't understand this either.

I need and would greatly appreciate any help tracking this problem down.

Thanks in advance.

[image: logo_170x100px.png] <http://www.gradiant.org/>

Julián Jiménez González

Investigador - Desarrollador | Área de Servicios y Aplicaciones

Researcher - Developer | Services & Applications Department

Ph. (+34) 986 120 430 Ext. 3021
jjimenez(at)gradiant(dot)org | www.gradiant.org

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