This blog describes a bug in most SAP PLM 7.x systems out there leveraging digital signatures. Before you continue, you might want to familiarize yourself with Digital Signatures in SAP PLM 7.x. I reported the problem described in this blog to SAP support on 01/26/15 and it was handled promptly by PLM Development Support and a solution was given on 02/13/15. Since there is a official fix available and since exploiting the bug requires system access, I feel confident exposing the problem in the current digital signature implementation.
In method HNDL_SIGN_POPUP of ABAP class /PLMU/CL_DIR_APPL_ASSIST the digital signature is committed to the database regardless if the signature was successful (Continue) or if it was cancelled (Cancel). The reason being that the event DIR_SAVE is triggered regardless. The digital signature will be saved in SIGNH, SIGNS and even DRAW_DS is updated to reflect the same but DRAP isn’t updated blocking anyone else from signing the document.
SAP released note 2120473 to address the issue. All customers live with SAP PLM 7.x should implement it to avoid digital signature corruption.