Malicious PDF — malware analysis report

Static analysis result for SHA-256 87aab2391bf0bb31…

MALICIOUS

PDF

80.8 KB Created: 2021-09-11 08:59:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: b744ebb43dafc7d039383ee9df31821f SHA-1: 45338bc414e93fb065cbdd63b293d85f2cec9eab SHA-256: 87aab2391bf0bb31e5306ff4dc8e53c6050947bbe8cc57283eb71a88f8e424f4
154 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and a link farm. The presence of embedded JavaScript suggests an attempt to execute code, likely for exploitation or to redirect users to malicious sites. The numerous external URIs, including one pointing to 'synerhu.ru', indicate a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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
  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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 https://synerhu.ru/uplcv?utm_term=batman+arkham+apk+download PDF link annotation
    • http://theurbanthinktank.com/files/36307154695.pdfIn PDF document text
    • http://solemarservizi.it/userfiles/files/67912494971.pdfIn PDF document text
    • https://rdsdealers.com/ckfinder/userfiles/files/kilafusosel.pdfIn PDF document text
    • http://uniroll.pl/user_images/file/jixewugoviluwudur.pdfIn PDF document text
    • http://tiszaladany.hu/upload/file/tujuvaxofagukiwavefudi.pdfIn PDF document text
    • http://sziszolg.hu/editor_up/45583869826.pdfIn PDF document text
    • http://ayrh.internet-match.com/upload/files/walerupumif.pdfIn PDF document text
    • http://biemmecommerciale.eu/userfiles/files/ninowaw.pdfIn PDF document text
    • https://dejavuruse.com/userfiles/file/80052736117.pdfIn PDF document text
    • https://premiersuli.hu/files/files/vaviwimofesawexurajanijo.pdfIn PDF document text
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161328e049ebf7---45017369289.pdfIn PDF document text
    • https://sporyolu.com/resimler/files/48621685745.pdfIn PDF document text
    • http://www.dagmarsvendova.cz/admin/js/ckfinder/userfiles/files/21601053974.pdfIn PDF document text
    • http://maymaygiaydachidang.com/upload/files/nomobujoxifupu.pdfIn PDF document text
    • http://tindangnhadat.vn/upload/files/84719893387.pdfIn PDF document text
    • http://hyunsin.net/userfiles/file/jimuvovitusafepitelerax.pdfIn PDF document text
    • http://allegroescrow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161304ab7e9a6d---44969654928.pdfIn PDF document text
    • http://aumnat2car.com/ckfinder/core/connector/php/upload/files/korufodelajiruvopitafudo.pdfIn PDF document text
    • http://aotwcasino.com/ckfinder/userfiles/files/68443034973.pdfIn PDF document text
    • https://tdfstore.it/file/wizifewug.pdfIn PDF document text
    • https://divinenine.net/userfiles/file/sulumu.pdfIn PDF document text
    • http://pokwuttibut.com/file_media/file_image/file/55882731542.pdfIn PDF document text
    • http://wordtmann.beckbauer.eu/ckfinder/userfiles/files/28094887607.pdfIn PDF document text
    • http://aranysolyomfeszke.hu/editor_up/ravuzewizutiraxivobuf.pdfIn PDF document text
    • 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_off0000d3da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3DA 10496 bytes
SHA-256: 8acfbd372e77d3057a7d3687daad80a120faa3aa064c92bbc6633289adc747b8
font_01_sfnt_off0000eb87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB87 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010399.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10399 19512 bytes
SHA-256: f8a003972b013f107c8b9d030eff00af876842e638d32ea2e6e2d97c67134f84