Riba is haraam for the one who takes it and the one who pays it, and it is haraam to help with it in any way whatsoever

Firstly: 

Auditing the accounts of customers who deal with riba is haraam work,
because it involves approving of riba, writing it down, and keeping quiet
about it and not denouncing it. 

Please
see the answers to questions no. 108105,
118189 and 175492. 

Secondly: 

Muslim
(1598) narrated that Jaabir said: The Messenger of Allah (blessings and
peace of Allah be upon him) cursed the one who consumes riba and the one who
pays it, the one who writes it down and the two who witness it, and he said:
they are all the same. 

Shaykh
Ibn ‘Uthaymeen (may Allah have mercy on him) said: 

That
is, (they are all the same) in terms of being cursed, because they
co-operated in that.

End
quote from Fataawa Noor ‘ala ad-Darb, 16/2 

Imam
al-Bukhaari (may Allah have mercy on him) referred to this hadeeth that was
narrated by Imam Muslim in the title which he gave to a chapter of his
Saheeh, which he called: Chapter on the one who consumes riba, the one
who witnesses it and the one who writes it down. 

Then
he quoted two hadeeths in this chapter, one of which was the hadeeth of
‘Aa’ishah: When the last part of al-Baqarah was revealed, the Prophet
(blessings and peace of Allah be upon him) recited it, then he forbade trade
in alcohol. The second hadeeth is the hadeeth of Samurah, according to which
the Prophet (blessings and peace of Allah be upon him) said: “Last night, I
dreamt that two men came to me and took me out to a sacred land, then we set
out until we came to a river of blood in which a man was standing, and on
the bank of the river there was another man in front of whom were some
rocks. The man who was in the river came, and when he wanted to get out, the
(other) man threw a rock in his mouth, and sent him back to where he had
been. Every time he came and wanted to get out, he threw a rock into his
mouth and sent him back to where he had been. I said: ‘What is this?’ He
said: ‘The one who you saw in the river is the one who consumed riba.’ 

Al-Haafiz Ibn Hajar (may Allah have mercy on him) said: 

Ibn
at-Teen said: There is no mention in these two hadeeths of the one who
writes down riba and the one who witnesses it. My response is that he
mentioned them by implication because they help the one who consumes it to
do so. This only applies to the one who helps the one who is engaging in
riba. As for the one who writes it down or who witnesses the deal in order
to tell exactly what happened, this is a good intention and is not
included in the warning mentioned. Rather what is included is the one who
helps the one who is engaging in riba by writing it down and witnessing it;
his status is the same as that of the one who says “Trading
is only like Riba (usury)”
[al-Baqarah 2:275].
End quote. 

Shaykh
Ibn ‘Uthaymeen (may Allah have mercy on him) said: 

The
one who helps another to commit sin will incur a burden of sin as much as he
deserves. It is proven that the Prophet (blessings and peace of Allah be
upon him) cursed the one who consumes riba, the one who pays it, the two who
witness it and the one who writes it down, because the two witnesses and the
one who writes it down are helping to confirm this transaction, so they
incur whatever they deserve of the curse. 

End
quote from al-Liqa’ ash-Shahri, 35/24 

In
fact what we have previously affirmed on our website does not differ in the
slightest from what we have quoted here and what the questioner has quoted
from al-Haafiz Ibn Hajar or from al-Abi (may Allah have mercy on them
both). 

Auditing bank accounts or the accounts of riba-based companies comes under
the heading of helping in the haraam riba transaction and participating in
it; it is not possible to complete riba-based deals without the help of
accountants. 

But
there remain these two forms that are not included in haraam writing down or
witnessing: 

1.

Where
one witnesses or writes down the deal in order to document it and testify to
the involvement of the people who are party to it, as was mentioned by
al-Haafiz Ibn Hajar (may Allah have mercy on him). This is like one who sees
a crime such as murder or theft taking place, so he takes pictures, or he
writes down what happened, so that he may give testimony concerning it
before the judge and help to catch the perpetrator and help justice. This
person has nothing to do with the criminal act and therefore has nothing to
do with the perpetrator. And he is not helping with the sin or crime in any
way whatsoever; rathe, in fact he was striving to change evil and establish
justice to the best of his ability. 

This
is what al-Haafiz Ibn Hajar (may Allah have mercy on him) was referring to,
and in our previous answers we were not suggesting that this kind of action
is haraam; rather it is something that is Islamically prescribed and is
necessary.

 2.

Where
a person or company or accounts department enters into a transaction with
another person or company or firm that deals with riba or other haraam
transactions, but the first party has nothing to do with its haraam actions;
rather he or they are dealing with them within the limits of permissible
transactions and contracts. 

For
example, the company may be dealing with riba-based transactions, but my job
is supervising a permissible project that does not involve any riba-based
transactions, or their riba-based transactions are between them and the
bank, and someone else takes care of dealing with customers, buying and
selling and so on, which has nothing to do with the riba-based transactions.
In such cases, there is no blame on the one who deals with the company or
plays any part in it. We have never disallowed this type of involvement
before; rather we stated clearly that this is permissible 

Shaykh
Ibn ‘Uthaymeen said: 

It is
permissible for a person to deal with someone who deals with riba, but his
interactions with him are done in a sound manner. For example, it is
permissible to buy goods from this man who deals in riba, and it is
permissible to borrow money from him, and there is nothing wrong with that.
The Prophet (blessings and peace of Allah be upon him) used to interact with
the Jews, even though they used to consume haraam wealth; he used to accept
their gifts and invitations, and he bought and sold with them too. 

To sum
up: if a person earns money from haraam sources but you deal with him in a
permissible transaction, there is no blame on you for doing so.

End
quote from Fataawa Noor ‘ala ad-Darb, 16/2 

See
also the answers to questions no. 171145 and
11315 

And
Allah knows best.