Malicious PDF — malware analysis report

Static analysis result for SHA-256 98ebcc88fe091251…

MALICIOUS

PDF

73.1 KB Created: 2021-06-28 16:09:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3aabb6224491c53814a42ccdb9422b6a SHA-1: 8a04e31af9d830286da9561587ee76302bf19be4 SHA-256: 98ebcc88fe0912511a80fb37832d9d4c0117563ad1eb5bd262b4d26f9020bad0
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate the presence of link farms pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to distribute further payloads or phish for credentials. The embedded URLs, particularly those with 'zkaccess 3.5 security system download' in the query parameters, reinforce the lure of a fake software download.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://egf.tw/test2/images/file/kiwuzekum.pdf
    • http://winso.tw/userfiles/file/zumizeselepiw.pdf
    • https://apparel.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/349f308e94e37260cadf50eff34275d2/32406106510.pdf
    • https://aguiapromocional.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c5834d8406d---robomaboguruj.pdf
    • https://alignerco.com/wp-content/plugins/super-forms/uploads/php/files/99753505e86e02ee3a8c212cc779324a/remasixatede.pdf
    • https://www.idromeccanicasrl.com/idromeccanicasrl.com/wp-content/plugins/super-forms/uploads/php/files/29f850aa60f6eafd0801038bbc4b5715/67199648250.pdf
    • https://wecareprogram.org/images/file/62644531823.pdf
    • https://portsidestrategies.com/wp-content/plugins/super-forms/uploads/php/files/72ea7f3f6a0cc1f028e7aacf34fa0878/jopixetukelunasajipilof.pdf
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fa79762fe9---13087240117.pdf
    • http://www.cargeacrew.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16094a94a198ef---vogiredotojutafivum.pdf
    • https://technok.cz/wp-content/plugins/super-forms/uploads/php/files/9878548c426391586162545dce98e600/30253746066.pdf
    • https://www.generalutilities.com/wp-content/plugins/formcraft/file-upload/server/content/files/160709c6ae285f---45318479848.pdf
    • https://boldvision.tv/wp-content/plugins/formcraft/file-upload/server/content/files/160a2ea34bc3ac---fezuvotatibezozatulet.pdf
    • http://conwaychristian.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b62c22d49a7---kabiwawosiniwixipebuxiw.pdf
    • http://chiengthai.com/file_media/file_image/file/lisego.pdf
    • http://worksafeorg.com/wp-content/plugins/super-forms/uploads/php/files/hqafpfqi5qrnka6hh048ot3f47/51935043912.pdf
    • https://dmvassociates.com/wp-content/plugins/super-forms/uploads/php/files/c6f45449401ec072890bdd0d5f214a42/98353030535.pdf
    • https://audreyheselmans.com/_files/file/vojutuvorijo.pdf
    • https://www.partyshuttlebus.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160b5de2308db7---xadujarekopori.pdf
    • https://www.auditek.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16085139f2ac79---72744871473.pdf
    • https://too.kg/wp-content/plugins/super-forms/uploads/php/files/284ace4f38045a84e95c94fa86880343/76356995843.pdf
    • https://3dreamstudios.com/wp-content/plugins/super-forms/uploads/php/files/8bb3ef795d9c936c33c4ab4f56f2a032/95564553975.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=zkaccess+3.5+security+system+download
    • 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_off0000bbc5.bin
06855b5fac5946d91e496fea4ca050661cd476ad4d6d6e9bd6fc097dffde7132
pdf-font-stream PDF embedded font (sfnt) at offset 0xBBC5 15748 bytes
font_01_sfnt_off0000e483.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE483 16792 bytes
font_02_sfnt_off0000fc9a.bin
ad7dfbe4510f8d66d5b6e81aa6f79ec953fc08469be9c7350b3ad95585b8a9aa
pdf-font-stream PDF embedded font (sfnt) at offset 0xFC9A 11260 bytes