We find an efficient method to solve the semidirect discrete logarithm problem (SDLP) over finite nonabelian groups of order p3{p}^{3} and exponent p2{p}^{2} for certain exponentially large parameters. This implies an attack on SPDH-Sign,Pronounced “SPUD-Sign”. a signature scheme based on the SDLP, for such parameters. In particular, SDLP instances over such groups are parameterised by an n