By Paul Cruickshank
A purported new issue of an English-language al Qaeda magazine linked to the Boston terrorist attacks was posted on an al Qaeda web forum earlier this week, but its content beyond its cover page was scrambled, suggesting the possibility the forum was hacked by Western intelligence agencies.
The magazine, produced by al Qaeda's Yemeni affiliate - al Qaeda in the Arabian Peninsula, which regularly includes how-to instructions for followers to carry out terrorist attacks in the West - has received significant scrutiny in recent weeks.
Investigators believe that Boston bomber Tamerlan Tsarnaev accessed Inspire magazine, and the material had instructions on bomb-making, a law enforcement official told CNN earlier this month.
According to analysts, the explosive devices the Boston bombers built had striking similarities to a bomb recipe in the first issue of the magazine - "How to build a bomb in your Mom's kitchen" - that has been downloaded by militants in multiple Islamist terrorist plots on both sides of the Atlantic.
The purported new issue of Inspire magazine was located by Flashpoint Partners, an American outfit that tracks jihadist websites. Josh Lefkowitz, a senior partner at Flashpoint, said they detected the new posting on the administrator account of the top-tier, password-protected forum Al Fidaa - a website regularly used to disseminate propaganda from al Qaeda and its affiliates - Tuesday evening.
All the links led to the same corrupted PDF file, and within minutes, the posting had been deleted from the web forum completely.
The purported new issue titled "How did it come to this?" was dated "Spring 2013" and contained no mention of the Boston attack on its cover page, which CNN has obtained.
Previous issues of Inspire magazine have seen intervals of weeks to months between production and final publication. According to Flashpoint's analysis, the metadata on the new purported Inspire magazine shows it was last modified on April 8, a week before the Boston bombings. Metadata is electronic data on the creation and modification of files,but it can itself be corrupted.
The cover page included a content caption "Open Source Jihad," which in past issues has been a section featuring do-it-yourself terrorism advice.
Lefkowitz says there are several possible explanations for the scrambled file, ranging from a hoax perpetrated by a sophisticated hacker to intervention from intelligence agencies.
What seems not to be in doubt, he said, is that someone hacked the al Qaeda web forum.
He pointed out that when the first issue of Inspire was released in summer 2010, its content was similarly scrambled. According to the Washington Post, computer experts working for the British government deliberately garbled several sections of the magazine when it was posted online. Two weeks later AQAP released a new, corrected version of the magazine.
Lefkowitz said it is thought Western intelligence often has a window in which to disrupt al Qaeda publications before they are posted on password protected forums because the online mechanics of creating such postings - and connecting the content to multiple web links to ensure it can be downloaded - takes time.
Lefkowitz also noted that Al Shamukh, another top-tier al Qaeda web forum, went down 30 minutes after Inspire magazine was posted on Al Fidaa in what appears to have been a denial of service attack. Late Thursday the site continued to be down, according to Flashpoint partners.
Such is the concern about Inspire magazine that authorities in the UK have adopted a zero-tolerance approach to those accessing Inspire. More than 20 individuals have been arrested and prosecuted in the UK in the past 18 months for downloading the magazine, the London Times reported earlier this month.