PDF malware analysis — malicious · 67921e926f0ff2e9

MALICIOUS

PDF

56.8 KB Created: 2021-06-07 04:13:07 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-16

MD5: 57f5fc902fe8ccefbf8609a021b6938b SHA-1: c3dc0fe9fcbe94561347eb61977c5abfdc2f7e2b SHA-256: 67921e926f0ff2e979771ac9dc29d14de3c40c286cfbf7a75284133540fe38c6

240 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF document contains a malformed stream and links to known malicious redirector infrastructure, specifically promoting 'free Robux' and game hacks. The primary lure URL is https://netcdn.tw/app/431946152/free-robux-for-free-no-human-verification-game-hack, which is part of a link farm designed to attract users searching for in-game currency or cheats. The document's structure and embedded links suggest an attempt to exploit user interest in free virtual goods to redirect them to potentially harmful sites.

Machine Learning

Nyx PDF Classifier malicious score 0.9753

Heuristics 6

PDF links to a 'free generator / game hack' redirector critical PDF_GAME_HACK_REDIRECT_LURE

PDF's clickable action targets a redirector of the form /app/<id>/<slug>-game-hack — the landing-page shape of a large SEO 'free spins / generator / game hack' lure family that funnels victims through rotating disposable hosts to a malware/scam payload. The multi-link variants also trip ML/link-farm rules; this catches the single-link variants that otherwise score clean. CRITICAL on its own: the /app/<id>/<slug>-game-hack path shape is unambiguous scam infra, and the host rotates so a host-list match can't be relied on.
PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK

PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM

Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH

A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON

Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL https://netcdn.tw/app/431946152/free-robux-for-free-no-human-verification-game-hack In PDF document text
- http://heilzentrum-ulm.de/images/pubg-74-uc_GM1330123889.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/coin-master-hack-online-without-human-verification_GM406889139.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/pubg-uc-rate-in-india_GM1330123889.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/will-minecraft-ever-be-free_GM479516143.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/free-roblox-accounts-with-robux-2021-november_GM431946152.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/free-robux-generator_GM431946152.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/funny-free-roblox-t-shirt_GM431946152.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/how-can-i-get-free-coinsn-coin-master_GM406889139.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/coin-master-heaven-free-spins-today_GM406889139.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/bux-free-robux_GM431946152.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/robux-com-free-robux_GM431946152.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/free-robux-hacks-no-verification_GM431946152.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/all-of-the-free-roblox-clothes_GM431946152.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/free-minecraft-mods_GM479516143.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/how-to-hack-a-minecraft-server_GM479516143.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/free-minecraft-svg-cutting-files_GM479516143.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/pubg-mobile-uc-xyz_GM1330123889.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/regal-world-coin-master_GM406889139.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/coinmaster-gps-user-review-coinmaster-coin-master-hack-pagedemo-index_GM406889139.pdfIn PDF document text
- http://heilzentrum-ulm.de/images/free-tiktok-likes-generator_GM835599320.pdfIn PDF document text
- http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`stream_004_off0000550b.bin`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x550B	26120 bytes
SHA-256: `f73568f60d20440fe17e94c1eb6efa34a49c1f15f1d781eca9992a3e84128b83`
`font_01_sfnt_off00009255.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0x9255	12800 bytes
SHA-256: `db399d969d9309c9c38cb6e3c43aa83c06d227a5470715de93176d1df1e6747d`
`font_02_sfnt_off0000ba32.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0xBA32	18860 bytes
SHA-256: `7bf6b254896799c3550cbaf8339a45bd8c79022df116fd793fc899e49cde55bc`

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