Header:

@interface NSAttributedString (NSAttributedString_MoreExtensions)

/** 
 * @method allAttachments 
 * @abstract Fetchs all attachments from an NSAttributedString. 
 * @discussion This method searchs for NSAttachmentAttributeName attributes within the string instead of searching for NSAttachmentCharacter characters. 
 */
- (NSArray *)allAttachments;

@end

Source:

@implementation NSAttributedString (NSAttributedString_MoreExtensions)
- (NSArray *)allAttachments
{
NSMutableArray *theAttachments = [NSMutableArray array];
NSRange theStringRange = NSMakeRange(0, [self length]);
if (theStringRange.length > 0)
    {
    unsigned N = 0;
    do
        {
        NSRange theEffectiveRange;
        NSDictionary *theAttributes = [self attributesAtIndex:N longestEffectiveRange:&theEffectiveRange inRange:theStringRange];
        NSTextAttachment *theAttachment = [theAttributes objectForKey:NSAttachmentAttributeName];
        if (theAttachment != NULL)
            [theAttachments addObject:theAttachment];
        N = theEffectiveRange.location + theEffectiveRange.length;
        }
    while (N < theStringRange.length);
    }
return(theAttachments);
}

@end