This item used to drop from Rohh the Silent, a then level 26 mob, and has since changed to level 18 as of the Cataclysm. The dagger now has a too high item level to drop from him.
However, it was recently discovered that this item IS obtainable from Battered Junkboxes circa Patch 5.4.7, with an extremely low drop rate(0.001%). A GM supposedly confirmed it still drops as of Patch 5.2. Users on the item's Wowhead page have discussed the best methods to farm the dagger in the comments section.
Patch changes Edit
- Patch 6.0.2 (14-October-2014): Stat squished from damage 21 - 39 (DPS 18.9) to damage 11 - 21 (DPS 8.99), but bonus increased to +8 Agility from +1 Agility. 1 - 7 bonus shadow damage removed.
- Patch 1.11.1 (28-Jun-2006): Added.