Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5542f87822af83d…

MALICIOUS

PDF

76.0 KB Created: 2021-09-05 14:17:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 8a0c2caf633ffdeac85b32ce740b03cd SHA-1: 7fc35f62b370e4a2151a601779f0194367a779ad SHA-256: b5542f87822af83d62ccd72701187d0986f55c732dee67b4ab1de399279f1bbd
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous URLs, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and unreadable, providing no direct content clues, but the heuristics strongly indicate a phishing or malware distribution attempt via embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://rajaunited.com/contents//files/visisobavin.pdf In PDF document text
    • http://pcwenhua.com/uploadimg/file/162395174672644264.pdfIn PDF document text
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/16120c4e34f0e3---rujijasedawiduvulazipi.pdfIn PDF document text
    • https://www.enterpriselighting.com/wp-content/plugins/super-forms/uploads/php/files/8425d5d4cc7496f88b4d69c35190d3d9/memalegenenulajudadamituk.pdfIn PDF document text
    • https://rzfmuhasebe.com/userfiles/file/82867537674.pdfIn PDF document text
    • https://kompaspt1.com/contents//files/81165030362.pdfIn PDF document text
    • http://ozgu-yapi.com/firma/files/nixajubafekitipu.pdfIn PDF document text
    • http://s4l.vn/storage/ckfinder/files/66128323300.pdfIn PDF document text
    • https://nedimgame.net/calisma2/files/uploads/bavase.pdfIn PDF document text
    • https://editionsitaliques.com/userfiles/file/64005303716.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/1mloclvjrr315k01jppn8sh9k4/89664785709.pdfIn PDF document text
    • http://furkansigorta.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160869f65d81d5---lotobexijolidufuvodere.pdfIn PDF document text
    • http://yaqeen-eg.com/userfiles/file/muzosonidokalosevuxe.pdfIn PDF document text
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160e550ed29785---gibokakawubigeb.pdfIn PDF document text
    • http://allseasonsart.com/uploads/fck_uploads/file/3181745307.pdfIn PDF document text
    • http://a2itsolutions.com/chop/multimedia/userfiles/file/bumig.pdfIn PDF document text
    • http://korean-school.hu/hangul/userfiles/file/nefiwimekafo.pdfIn PDF document text
    • http://mobydick-band.de/fckdata/file/zejuf.pdfIn PDF document text
    • https://www.charityweiss.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608f1eaea3635---92598397219.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d0c477b8aeb---88449179717.pdfIn PDF document text
    • http://seabeachthailand.com/UserFiles/file/24773847235.pdfIn PDF document text
    • https://mldom.xyz/web/img/podborky/files/83848996892.pdfIn PDF document text
    • http://www.thediethub.in/wp-content/plugins/formcraft/file-upload/server/content/files/160904ecb34385---53815504554.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=halloween+worksheets+for+first+gradePDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c5de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC5DE 16992 bytes
SHA-256: 5c2d70337d7aef4f454066033d6b95e5914c97b92e2ead59b185dfe45a6658ea
font_01_sfnt_off0000f1e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1E3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000109fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109FA 10804 bytes
SHA-256: 87f09cd338fdddf8d086ae3f5f0d592ba9c79f3951d75b2380759c230e573d8a