Malicious PDF — malware analysis report

Static analysis result for SHA-256 991fa0ced55dcc28…

MALICIOUS

PDF

77.2 KB Created: 2021-09-12 22:56:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4d844a2e79882bb116e9f7ee6d7827c1 SHA-1: b51e72380e8a965b20a63b30a614e5c913af3e1b SHA-256: 991fa0ced55dcc288b213757d35772e9e7ef40d00130161cd563df8a3a011887
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous external URIs, many of which point to PDF files hosted on disposable or potentially compromised domains. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or SEO poisoning campaigns. The presence of JavaScript suggests an attempt to execute malicious code, potentially to download further payloads or redirect the user.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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 http://zs-g.jp/app/webroot/js/ckfinder/userfiles/files/95708916574.pdf
    • http://cautrucpalang.vn/webroot/img/files/38922616341.pdf
    • http://klick-tipp.info/ckfinder/userfiles/publics/files/tumegudalukebularevamex.pdf
    • https://togeltop.net/contents/files/busajezozikusexekoj.pdf
    • http://songhakbbq.com/uploads/files/tiginumidepixurabix.pdf
    • https://mudateconmigo.cl/wp-content/plugins/super-forms/uploads/php/files/034991bab3e09d75fd9533a4d71a95ea/noravukamaxaduwer.pdf
    • http://huntland.hu/upload/file/54264285613.pdf
    • http://teleinwestor.com/userfiles/file/govejejudusevov.pdf
    • https://skopjemuzikon.pmgrecordings.com/ckfinder/userfiles/files/14978172046.pdf
    • http://ingore.cn/upload/files/35523469873.pdf
    • http://woodwaysindia.com/uploads/87914390492.pdf
    • http://erpsamik.com/ckfinder/userfiles/files/47588313592.pdf
    • https://proartgaleria.hu/files/files/gebekopabikasosalosed.pdf
    • http://hanleyresources.com/images/68744226000.pdf
    • http://aldobini.it/userfiles/files/35770189985.pdf
    • http://rosabaum.de/web/editor/files/dolapiveduxenevezogugul.pdf
    • https://k-kompany.ru/wp-content/plugins/super-forms/uploads/php/files/1e1a9265fb8e01abd598a25bebdf37cd/39551841307.pdf
    • http://teknis.it/userfiles/files/muvivaderijiwotiti.pdf
    • https://history.tlshaa.org.tw/ckfinder/userfiles/files/87185527967.pdf
    • https://zerling.eu/nico/images/files/86886667973.pdf
    • https://abcoegypt.com/userfiles/files/98394655525.pdf
    • https://mannerfeltdesignteam.se/ckfinder/userfiles/files/jonudebewazufi.pdf
    • http://didopack.com/files/21963573348.pdf
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/ufull8gtit7e74ge2hn3dniroj/valafuzulisivese.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=insta+bio+viewer
    • http://alessandrotria.altervista.org/areap/ckfinder/userfiles/files/17871558291.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • 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_off0000c9ed.bin
d0411efc5be113d4049fe693cfadfc77655147a9a881652afe8b627b2eab0f9b
pdf-font-stream PDF embedded font (sfnt) at offset 0xC9ED 17612 bytes
font_01_sfnt_off0000f78e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF78E 16792 bytes
font_02_sfnt_off00010fa5.bin
a6ff25358d1646ddc203c3bbe242a616f5fd12082be551d466a26ea2127ad99b
pdf-font-stream PDF embedded font (sfnt) at offset 0x10FA5 10300 bytes