Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b79ec819b3a827f…

MALICIOUS

PDF

80.2 KB Created: 2021-09-18 16:01:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 56bde240264d153c4c8a1e44f25a981a SHA-1: f0058ff60a5372a31f5a8b6d185d6dfece2400e3 SHA-256: 8b79ec819b3a827f457860e8d5496fb0acbb551307525c274be36ec3890a63a8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs that point to various domains, many of which are associated with link farms and compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct content clues, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://medvor.ru/uplcv?utm_term=apps+are+not+installing+in+my+phone
    • http://shanghaiqingchen.com/upload/files/49336651778.pdf
    • http://warmistore.com/userfiles/file/77801624750.pdf
    • http://xn--tnqz8hz5cb8l.com/upload/files/fugakasifopaxa.pdf
    • https://epagneuls-bretons.fr/caningest/images/file/99252770033.pdf
    • https://master.plus/wp-content/plugins/super-forms/uploads/php/files/868794cf7f40ef0b430d2e10f6e020ce/zawazu.pdf
    • http://moneymaker-gold.de/files/56564510393.pdf
    • http://kondicionery-himki.ru/upload_picture/file/fawutegil.pdf
    • http://zge-led.com/luodan/images/userfiles/file/52301442051.pdf
    • https://lifesmart.ro/ckfinder/userfiles/files/83720072035.pdf
    • http://torgradio.ru/new/files/file/gutobopofe.pdf
    • http://hillsdalehorseboarding.com/ckfinder/userfiles/files/rolimuxosibijifozidu.pdf
    • http://romovi.net/sgi_userfiles/userfiles/files/vikilaperosokuxizinikuxa.pdf
    • https://pemaboutiquehotel.com/assets/userfiles/files/famotigodedepexuxifodu.pdf
    • http://matstravel.ru/userfiles/file/66716328767.pdf
    • http://zajazd-broadway.pl/galeria/file/44516752346.pdf
    • https://autotrilogy.com/wp-content/plugins/super-forms/uploads/php/files/c144b2d6273075ec37f519b155cb7f3a/jopawi.pdf
    • http://wasserentkalkung.at/ckfinder/userfiles/files/1996406824.pdf
    • http://canoeing.by/pics/files/25809251328.pdf
    • http://footstepfloor.com/upfiles/files/71499076865.pdf
    • http://loaamtran.vn/files/usersfiles/files/29753084161.pdf
    • https://onutglen.com/caningest/images/file/gapojowesufuzutejuv.pdf
    • http://qdjshg.com/files/file/petuzazus.pdf
    • http://www.combatsim.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16141138db91fc---butikanuvazamezirijexaj.pdf
    • http://e3edu.vn/public/ckfinder/core/connector/php/connector.phppublic/uploadsfiles/patuzavemekajasifim.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d7d3.bin
69a1280299a2e20a11b4ccaf91c9fc72436b081d3217e21f1e2cbb00a0466271
pdf-font-stream PDF embedded font (sfnt) at offset 0xD7D3 17720 bytes
font_01_sfnt_off0001053a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1053A 16792 bytes
font_02_sfnt_off00011d51.bin
909a8e7adeb1169fc8afc22cd2101de62891b59fe8bfe51bee990fcaaa88746c
pdf-font-stream PDF embedded font (sfnt) at offset 0x11D51 10792 bytes